13 "github.com/mjl-/mox/autotls"
14 "github.com/mjl-/mox/dns"
15 "github.com/mjl-/mox/junk"
16 "github.com/mjl-/mox/mtasts"
17 "github.com/mjl-/mox/smtp"
20// todo: better default values, so less has to be specified in the config file.
22// DefaultMaxMsgSize is the maximum message size for incoming and outgoing
23// messages, in bytes. Can be overridden per listener.
24const DefaultMaxMsgSize = 100 * 1024 * 1024
26// Port returns port if non-zero, and fallback otherwise.
27func Port(port, fallback int) int {
34// Static is a parsed form of the mox.conf configuration file, before converting it
35// into a mox.Config after additional processing.
37 DataDir string `sconf-doc:"NOTE: This config file is in 'sconf' format. Indent with tabs. Comments must be on their own line, they don't end a line. Do not escape or quote strings. Details: https://pkg.go.dev/github.com/mjl-/sconf.\n\n\nDirectory where all data is stored, e.g. queue, accounts and messages, ACME TLS certs/keys. If this is a relative path, it is relative to the directory of mox.conf."`
38 LogLevel string `sconf-doc:"Default log level, one of: error, info, debug, trace, traceauth, tracedata. Trace logs SMTP and IMAP protocol transcripts, with traceauth also messages with passwords, and tracedata on top of that also the full data exchanges (full messages), which can be a large amount of data."`
39 PackageLogLevels map[string]string `sconf:"optional" sconf-doc:"Overrides of log level per package (e.g. queue, smtpclient, smtpserver, imapserver, spf, dkim, dmarc, dmarcdb, autotls, junk, mtasts, tlsrpt)."`
40 User string `sconf:"optional" sconf-doc:"User to switch to after binding to all sockets as root. Default: mox. If the value is not a known user, it is parsed as integer and used as uid and gid."`
41 NoFixPermissions bool `sconf:"optional" sconf-doc:"If true, do not automatically fix file permissions when starting up. By default, mox will ensure reasonable owner/permissions on the working, data and config directories (and files), and mox binary (if present)."`
42 Hostname string `sconf-doc:"Full hostname of system, e.g. mail.<domain>"`
43 HostnameDomain dns.Domain `sconf:"-" json:"-"` // Parsed form of hostname.
44 CheckUpdates bool `sconf:"optional" sconf-doc:"If enabled, a single DNS TXT lookup of _updates.xmox.nl is done every 24h to check for a new release. Each time a new release is found, a changelog is fetched from https://updates.xmox.nl/changelog and delivered to the postmaster mailbox."`
45 Pedantic bool `sconf:"optional" sconf-doc:"In pedantic mode protocol violations (that happen in the wild) for SMTP/IMAP/etc result in errors instead of accepting such behaviour."`
48 AdditionalToSystem bool `sconf:"optional"`
49 CertFiles []string `sconf:"optional"`
51 CertPool *x509.CertPool `sconf:"-" json:"-"`
52 } `sconf:"optional" sconf-doc:"Global TLS configuration, e.g. for additional Certificate Authorities. Used for outgoing SMTP connections, HTTPS requests."`
53 ACME map[string]ACME `sconf:"optional" sconf-doc:"Automatic TLS configuration with ACME, e.g. through Let's Encrypt. The key is a name referenced in TLS configs, e.g. letsencrypt."`
54 AdminPasswordFile string `sconf:"optional" sconf-doc:"File containing hash of admin password, for authentication in the web admin pages (if enabled)."`
55 Listeners map[string]Listener `sconf-doc:"Listeners are groups of IP addresses and services enabled on those IP addresses, such as SMTP/IMAP or internal endpoints for administration or Prometheus metrics. All listeners with SMTP/IMAP services enabled will serve all configured domains. If the listener is named 'public', it will get a few helpful additional configuration checks, for acme automatic tls certificates and monitoring of ips in dnsbls if those are configured."`
58 Mailbox string `sconf-doc:"E.g. Postmaster or Inbox."`
59 } `sconf-doc:"Destination for emails delivered to postmaster addresses: a plain 'postmaster' without domain, 'postmaster@<hostname>' (also for each listener with SMTP enabled), and as fallback for each domain without explicitly configured postmaster destination."`
61 Account string `sconf-doc:"Account to deliver TLS reports to. Typically same account as for postmaster."`
62 Mailbox string `sconf-doc:"Mailbox to deliver TLS reports to. Recommended value: TLSRPT."`
63 Localpart string `sconf-doc:"Localpart at hostname to accept TLS reports at. Recommended value: tls-reports."`
65 ParsedLocalpart smtp.Localpart `sconf:"-"`
66 } `sconf:"optional" sconf-doc:"Destination for per-host TLS reports (TLSRPT). TLS reports can be per recipient domain (for MTA-STS), or per MX host (for DANE). The per-domain TLS reporting configuration is in domains.conf. This is the TLS reporting configuration for this host. If absent, no host-based TLSRPT address is configured, and no host TLSRPT DNS record is suggested."`
67 InitialMailboxes InitialMailboxes `sconf:"optional" sconf-doc:"Mailboxes to create for new accounts. Inbox is always created. Mailboxes can be given a 'special-use' role, which are understood by most mail clients. If absent/empty, the following mailboxes are created: Sent, Archive, Trash, Drafts and Junk."`
68 DefaultMailboxes []string `sconf:"optional" sconf-doc:"Deprecated in favor of InitialMailboxes. Mailboxes to create when adding an account. Inbox is always created. If no mailboxes are specified, the following are automatically created: Sent, Archive, Trash, Drafts and Junk."`
69 Transports map[string]Transport `sconf:"optional" sconf-doc:"Transport are mechanisms for delivering messages. Transports can be referenced from Routes in accounts, domains and the global configuration. There is always an implicit/fallback delivery transport doing direct delivery with SMTP from the outgoing message queue. Transports are typically only configured when using smarthosts, i.e. when delivering through another SMTP server. Zero or one transport methods must be set in a transport, never multiple. When using an external party to send email for a domain, keep in mind you may have to add their IP address to your domain's SPF record, and possibly additional DKIM records."`
70 // Awkward naming of fields to get intended default behaviour for zero values.
71 NoOutgoingDMARCReports bool `sconf:"optional" sconf-doc:"Do not send DMARC reports (aggregate only). By default, aggregate reports on DMARC evaluations are sent to domains if their DMARC policy requests them. Reports are sent at whole hours, with a minimum of 1 hour and maximum of 24 hours, rounded up so a whole number of intervals cover 24 hours, aligned at whole days in UTC. Reports are sent from the postmaster@<mailhostname> address."`
72 NoOutgoingTLSReports bool `sconf:"optional" sconf-doc:"Do not send TLS reports. By default, reports about failed SMTP STARTTLS connections and related MTA-STS/DANE policies are sent to domains if their TLSRPT DNS record requests them. Reports covering a 24 hour UTC interval are sent daily. Reports are sent from the postmaster address of the configured domain the mailhostname is in. If there is no such domain, or it does not have DKIM configured, no reports are sent."`
73 OutgoingTLSReportsForAllSuccess bool `sconf:"optional" sconf-doc:"Also send TLS reports if there were no SMTP STARTTLS connection failures. By default, reports are only sent when at least one failure occurred. If a report is sent, it does always include the successful connection counts as well."`
74 QuotaMessageSize int64 `sconf:"optional" sconf-doc:"Default maximum total message size for accounts, only applicable if greater than zero. Can be overridden per account. Attempting to add new messages beyond the maximum size will result in an error. Useful to prevent a single account from filling storage. The quota only applies to the email message files, not to any file system overhead and also not the message index database file (account for approximately 15% overhead)."`
76 // All IPs that were explicitly listen on for external SMTP. Only set when there
77 // are no unspecified external SMTP listeners and there is at most one for IPv4 and
78 // at most one for IPv6. Used for setting the local address when making outgoing
79 // connections. Those IPs are assumed to be in an SPF record for the domain,
80 // potentially unlike other IPs on the machine. If there is only one address
81 // family, outgoing connections with the other address family are still made if
83 SpecifiedSMTPListenIPs []net.IP `sconf:"-" json:"-"`
85 // To switch to after initialization as root.
86 UID uint32 `sconf:"-" json:"-"`
87 GID uint32 `sconf:"-" json:"-"`
90// InitialMailboxes are mailboxes created for a new account.
91type InitialMailboxes struct {
92 SpecialUse SpecialUseMailboxes `sconf:"optional" sconf-doc:"Special-use roles to mailbox to create."`
93 Regular []string `sconf:"optional" sconf-doc:"Regular, non-special-use mailboxes to create."`
96// SpecialUseMailboxes holds mailbox names for special-use roles. Mail clients
97// recognize these special-use roles, e.g. appending sent messages to whichever
98// mailbox has the Sent special-use flag.
99type SpecialUseMailboxes struct {
100 Sent string `sconf:"optional"`
101 Archive string `sconf:"optional"`
102 Trash string `sconf:"optional"`
103 Draft string `sconf:"optional"`
104 Junk string `sconf:"optional"`
107// Dynamic is the parsed form of domains.conf, and is automatically reloaded when changed.
109 Domains map[string]Domain `sconf-doc:"NOTE: This config file is in 'sconf' format. Indent with tabs. Comments must be on their own line, they don't end a line. Do not escape or quote strings. Details: https://pkg.go.dev/github.com/mjl-/sconf.\n\n\nDomains for which email is accepted. For internationalized domains, use their IDNA names in UTF-8."`
110 Accounts map[string]Account `sconf-doc:"Accounts to which email can be delivered. An account can accept email for multiple domains, for multiple localparts, and deliver to multiple mailboxes."`
111 WebDomainRedirects map[string]string `sconf:"optional" sconf-doc:"Redirect all requests from domain (key) to domain (value). Always redirects to HTTPS. For plain HTTP redirects, use a WebHandler with a WebRedirect."`
112 WebHandlers []WebHandler `sconf:"optional" sconf-doc:"Handle webserver requests by serving static files, redirecting or reverse-proxying HTTP(s). The first matching WebHandler will handle the request. Built-in handlers, e.g. for account, admin, autoconfig and mta-sts always run first. If no handler matches, the response status code is file not found (404). If functionality you need is missng, simply forward the requests to an application that can provide the needed functionality."`
113 Routes []Route `sconf:"optional" sconf-doc:"Routes for delivering outgoing messages through the queue. Each delivery attempt evaluates account routes, domain routes and finally these global routes. The transport of the first matching route is used in the delivery attempt. If no routes match, which is the default with no configured routes, messages are delivered directly from the queue."`
115 WebDNSDomainRedirects map[dns.Domain]dns.Domain `sconf:"-" json:"-"`
119 DirectoryURL string `sconf-doc:"For letsencrypt, use https://acme-v02.api.letsencrypt.org/directory."`
120 RenewBefore time.Duration `sconf:"optional" sconf-doc:"How long before expiration to renew the certificate. Default is 30 days."`
121 ContactEmail string `sconf-doc:"Email address to register at ACME provider. The provider can email you when certificates are about to expire. If you configure an address for which email is delivered by this server, keep in mind that TLS misconfigurations could result in such notification emails not arriving."`
122 Port int `sconf:"optional" sconf-doc:"TLS port for ACME validation, 443 by default. You should only override this if you cannot listen on port 443 directly. ACME will make requests to port 443, so you'll have to add an external mechanism to get the connection here, e.g. by configuring port forwarding."`
123 IssuerDomainName string `sconf:"optional" sconf-doc:"If set, used for suggested CAA DNS records, for restricting TLS certificate issuance to a Certificate Authority. If empty and DirectyURL is for Let's Encrypt, this value is set automatically to letsencrypt.org."`
124 ExternalAccountBinding *ExternalAccountBinding `sconf:"optional" sconf-doc:"ACME providers can require that a request for a new ACME account reference an existing non-ACME account known to the provider. External account binding references that account by a key id, and authorizes new ACME account requests by signing it with a key known both by the ACME client and ACME provider."`
127 Manager *autotls.Manager `sconf:"-" json:"-"`
130type ExternalAccountBinding struct {
131 KeyID string `sconf-doc:"Key identifier, from ACME provider."`
132 KeyFile string `sconf-doc:"File containing the base64url-encoded key used to sign account requests with external account binding. The ACME provider will verify the account request is correctly signed by the key. File is evaluated relative to the directory of mox.conf."`
135type Listener struct {
136 IPs []string `sconf-doc:"Use 0.0.0.0 to listen on all IPv4 and/or :: to listen on all IPv6 addresses, but it is better to explicitly specify the IPs you want to use for email, as mox will make sure outgoing connections will only be made from one of those IPs."`
137 NATIPs []string `sconf:"optional" sconf-doc:"If set, the mail server is configured behind a NAT and field IPs are internal instead of the public IPs, while NATIPs lists the public IPs. Used during IP-related DNS self-checks, such as for iprev, mx, spf, autoconfig, autodiscover, and for autotls."`
138 IPsNATed bool `sconf:"optional" sconf-doc:"Deprecated, use NATIPs instead. If set, IPs are not the public IPs, but are NATed. Skips IP-related DNS self-checks."`
139 Hostname string `sconf:"optional" sconf-doc:"If empty, the config global Hostname is used."`
140 HostnameDomain dns.Domain `sconf:"-" json:"-"` // Set when parsing config.
142 TLS *TLS `sconf:"optional" sconf-doc:"For SMTP/IMAP STARTTLS, direct TLS and HTTPS connections."`
143 SMTPMaxMessageSize int64 `sconf:"optional" sconf-doc:"Maximum size in bytes for incoming and outgoing messages. Default is 100MB."`
146 Port int `sconf:"optional" sconf-doc:"Default 25."`
147 NoSTARTTLS bool `sconf:"optional" sconf-doc:"Do not offer STARTTLS to secure the connection. Not recommended."`
148 RequireSTARTTLS bool `sconf:"optional" sconf-doc:"Do not accept incoming messages if STARTTLS is not active. Consider using in combination with an MTA-STS policy and/or DANE. A remote SMTP server may not support TLS and may not be able to deliver messages. Incoming messages for TLS reporting addresses ignore this setting and do not require TLS."`
149 NoRequireTLS bool `sconf:"optional" sconf-doc:"Do not announce the REQUIRETLS SMTP extension. Messages delivered using the REQUIRETLS extension should only be distributed onwards to servers also implementing the REQUIRETLS extension. In some situations, such as hosting mailing lists, this may not be feasible due to lack of support for the extension by mailing list subscribers."`
150 // Reoriginated messages (such as messages sent to mailing list subscribers) should
153 DNSBLs []string `sconf:"optional" sconf-doc:"Addresses of DNS block lists for incoming messages. Block lists are only consulted for connections/messages without enough reputation to make an accept/reject decision. This prevents sending IPs of all communications to the block list provider. If any of the listed DNSBLs contains a requested IP address, the message is rejected as spam. The DNSBLs are checked for healthiness before use, at most once per 4 hours. Example DNSBLs: sbl.spamhaus.org, bl.spamcop.net. See https://www.spamhaus.org/sbl/ and https://www.spamcop.net/ for more information and terms of use."`
155 FirstTimeSenderDelay *time.Duration `sconf:"optional" sconf-doc:"Delay before accepting a message from a first-time sender for the destination account. Default: 15s."`
157 DNSBLZones []dns.Domain `sconf:"-"`
161 Port int `sconf:"optional" sconf-doc:"Default 587."`
162 NoRequireSTARTTLS bool `sconf:"optional" sconf-doc:"Do not require STARTTLS. Since users must login, this means password may be sent without encryption. Not recommended."`
163 } `sconf:"optional" sconf-doc:"SMTP for submitting email, e.g. by email applications. Starts out in plain text, can be upgraded to TLS with the STARTTLS command. Prefer using Submissions which is always a TLS connection."`
166 Port int `sconf:"optional" sconf-doc:"Default 465."`
167 } `sconf:"optional" sconf-doc:"SMTP over TLS for submitting email, by email applications. Requires a TLS config."`
170 Port int `sconf:"optional" sconf-doc:"Default 143."`
171 NoRequireSTARTTLS bool `sconf:"optional" sconf-doc:"Enable this only when the connection is otherwise encrypted (e.g. through a VPN)."`
172 } `sconf:"optional" sconf-doc:"IMAP for reading email, by email applications. Starts out in plain text, can be upgraded to TLS with the STARTTLS command. Prefer using IMAPS instead which is always a TLS connection."`
175 Port int `sconf:"optional" sconf-doc:"Default 993."`
176 } `sconf:"optional" sconf-doc:"IMAP over TLS for reading email, by email applications. Requires a TLS config."`
177 AccountHTTP WebService `sconf:"optional" sconf-doc:"Account web interface, for email users wanting to change their accounts, e.g. set new password, set new delivery rulesets. Default path is /."`
178 AccountHTTPS WebService `sconf:"optional" sconf-doc:"Account web interface listener like AccountHTTP, but for HTTPS. Requires a TLS config."`
179 AdminHTTP WebService `sconf:"optional" sconf-doc:"Admin web interface, for managing domains, accounts, etc. Default path is /admin/. Preferably only enable on non-public IPs. Hint: use 'ssh -L 8080:localhost:80 you@yourmachine' and open http://localhost:8080/admin/, or set up a tunnel (e.g. WireGuard) and add its IP to the mox 'internal' listener."`
180 AdminHTTPS WebService `sconf:"optional" sconf-doc:"Admin web interface listener like AdminHTTP, but for HTTPS. Requires a TLS config."`
181 WebmailHTTP WebService `sconf:"optional" sconf-doc:"Webmail client, for reading email. Default path is /webmail/."`
182 WebmailHTTPS WebService `sconf:"optional" sconf-doc:"Webmail client, like WebmailHTTP, but for HTTPS. Requires a TLS config."`
185 Port int `sconf:"optional" sconf-doc:"Default 8010."`
186 } `sconf:"optional" sconf-doc:"Serve prometheus metrics, for monitoring. You should not enable this on a public IP."`
189 Port int `sconf:"optional" sconf-doc:"Default 8011."`
190 } `sconf:"optional" sconf-doc:"Serve /debug/pprof/ for profiling a running mox instance. Do not enable this on a public IP!"`
191 AutoconfigHTTPS struct {
193 Port int `sconf:"optional" sconf-doc:"TLS port, 443 by default. You should only override this if you cannot listen on port 443 directly. Autoconfig requests will be made to port 443, so you'll have to add an external mechanism to get the connection here, e.g. by configuring port forwarding."`
194 NonTLS bool `sconf:"optional" sconf-doc:"If set, plain HTTP instead of HTTPS is spoken on the configured port. Can be useful when the autoconfig domain is reverse proxied."`
195 } `sconf:"optional" sconf-doc:"Serve autoconfiguration/autodiscovery to simplify configuring email applications, will use port 443. Requires a TLS config."`
198 Port int `sconf:"optional" sconf-doc:"TLS port, 443 by default. You should only override this if you cannot listen on port 443 directly. MTA-STS requests will be made to port 443, so you'll have to add an external mechanism to get the connection here, e.g. by configuring port forwarding."`
199 NonTLS bool `sconf:"optional" sconf-doc:"If set, plain HTTP instead of HTTPS is spoken on the configured port. Can be useful when the mta-sts domain is reverse proxied."`
200 } `sconf:"optional" sconf-doc:"Serve MTA-STS policies describing SMTP TLS requirements. Requires a TLS config."`
201 WebserverHTTP struct {
203 Port int `sconf:"optional" sconf-doc:"Port for plain HTTP (non-TLS) webserver."`
204 } `sconf:"optional" sconf-doc:"All configured WebHandlers will serve on an enabled listener."`
205 WebserverHTTPS struct {
207 Port int `sconf:"optional" sconf-doc:"Port for HTTPS webserver."`
208 } `sconf:"optional" sconf-doc:"All configured WebHandlers will serve on an enabled listener. Either ACME must be configured, or for each WebHandler domain a TLS certificate must be configured."`
211// WebService is an internal web interface: webmail, account, admin.
212type WebService struct {
214 Port int `sconf:"optional" sconf-doc:"Default 80 for HTTP and 443 for HTTPS."`
215 Path string `sconf:"optional" sconf-doc:"Path to serve requests on."`
216 Forwarded bool `sconf:"optional" sconf-doc:"If set, X-Forwarded-* headers are used for the remote IP address for rate limiting and for the \"secure\" status of cookies."`
219// Transport is a method to delivery a message. At most one of the fields can
220// be non-nil. The non-nil field represents the type of transport. For a
221// transport with all fields nil, regular email delivery is done.
222type Transport struct {
223 Submissions *TransportSMTP `sconf:"optional" sconf-doc:"Submission SMTP over a TLS connection to submit email to a remote queue."`
224 Submission *TransportSMTP `sconf:"optional" sconf-doc:"Submission SMTP over a plain TCP connection (possibly with STARTTLS) to submit email to a remote queue."`
225 SMTP *TransportSMTP `sconf:"optional" sconf-doc:"SMTP over a plain connection (possibly with STARTTLS), typically for old-fashioned unauthenticated relaying to a remote queue."`
226 Socks *TransportSocks `sconf:"optional" sconf-doc:"Like regular direct delivery, but makes outgoing connections through a SOCKS proxy."`
229// TransportSMTP delivers messages by "submission" (SMTP, typically
230// authenticated) to the queue of a remote host (smarthost), or by relaying
231// (SMTP, typically unauthenticated).
232type TransportSMTP struct {
233 Host string `sconf-doc:"Host name to connect to and for verifying its TLS certificate."`
234 Port int `sconf:"optional" sconf-doc:"If unset or 0, the default port for submission(s)/smtp is used: 25 for SMTP, 465 for submissions (with TLS), 587 for submission (possibly with STARTTLS)."`
235 STARTTLSInsecureSkipVerify bool `sconf:"optional" sconf-doc:"If set an unverifiable remote TLS certificate during STARTTLS is accepted."`
236 NoSTARTTLS bool `sconf:"optional" sconf-doc:"If set for submission or smtp transport, do not attempt STARTTLS on the connection. Authentication credentials and messages will be transferred in clear text."`
237 Auth *SMTPAuth `sconf:"optional" sconf-doc:"If set, authentication credentials for the remote server."`
239 DNSHost dns.Domain `sconf:"-" json:"-"`
242// SMTPAuth hold authentication credentials used when delivering messages
243// through a smarthost.
244type SMTPAuth struct {
247 Mechanisms []string `sconf:"optional" sconf-doc:"Allowed authentication mechanisms. Defaults to SCRAM-SHA-256-PLUS, SCRAM-SHA-256, SCRAM-SHA-1-PLUS, SCRAM-SHA-1, CRAM-MD5. Not included by default: PLAIN. Specify the strongest mechanism known to be implemented by the server to prevent mechanism downgrade attacks."`
249 EffectiveMechanisms []string `sconf:"-" json:"-"`
252type TransportSocks struct {
253 Address string `sconf-doc:"Address of SOCKS proxy, of the form host:port or ip:port."`
254 RemoteIPs []string `sconf-doc:"IP addresses connections from the SOCKS server will originate from. This IP addresses should be configured in the SPF record (keep in mind DNS record time to live (TTL) when adding a SOCKS proxy). Reverse DNS should be set up for these address, resolving to RemoteHostname. These are typically the IPv4 and IPv6 address for the host in the Address field."`
255 RemoteHostname string `sconf-doc:"Hostname belonging to RemoteIPs. This name is used during in SMTP EHLO. This is typically the hostname of the host in the Address field."`
257 // todo: add authentication credentials?
259 IPs []net.IP `sconf:"-" json:"-"` // Parsed form of RemoteIPs.
260 Hostname dns.Domain `sconf:"-" json:"-"` // Parsed form of RemoteHostname
264 Description string `sconf:"optional" sconf-doc:"Free-form description of domain."`
265 ClientSettingsDomain string `sconf:"optional" sconf-doc:"Hostname for client settings instead of the mail server hostname. E.g. mail.<domain>. For future migration to another mail operator without requiring all clients to update their settings, it is convenient to have client settings that reference a subdomain of the hosted domain instead of the hostname of the server where the mail is currently hosted. If empty, the hostname of the mail server is used for client configurations."`
266 LocalpartCatchallSeparator string `sconf:"optional" sconf-doc:"If not empty, only the string before the separator is used to for email delivery decisions. For example, if set to \"+\", you+anything@example.com will be delivered to you@example.com."`
267 LocalpartCaseSensitive bool `sconf:"optional" sconf-doc:"If set, upper/lower case is relevant for email delivery."`
268 DKIM DKIM `sconf:"optional" sconf-doc:"With DKIM signing, a domain is taking responsibility for (content of) emails it sends, letting receiving mail servers build up a (hopefully positive) reputation of the domain, which can help with mail delivery."`
269 DMARC *DMARC `sconf:"optional" sconf-doc:"With DMARC, a domain publishes, in DNS, a policy on how other mail servers should handle incoming messages with the From-header matching this domain and/or subdomain (depending on the configured alignment). Receiving mail servers use this to build up a reputation of this domain, which can help with mail delivery. A domain can also publish an email address to which reports about DMARC verification results can be sent by verifying mail servers, useful for monitoring. Incoming DMARC reports are automatically parsed, validated, added to metrics and stored in the reporting database for later display in the admin web pages."`
270 MTASTS *MTASTS `sconf:"optional" sconf-doc:"With MTA-STS a domain publishes, in DNS, presence of a policy for using/requiring TLS for SMTP connections. The policy is served over HTTPS."`
271 TLSRPT *TLSRPT `sconf:"optional" sconf-doc:"With TLSRPT a domain specifies in DNS where reports about encountered SMTP TLS behaviour should be sent. Useful for monitoring. Incoming TLS reports are automatically parsed, validated, added to metrics and stored in the reporting database for later display in the admin web pages."`
272 Routes []Route `sconf:"optional" sconf-doc:"Routes for delivering outgoing messages through the queue. Each delivery attempt evaluates account routes, these domain routes and finally global routes. The transport of the first matching route is used in the delivery attempt. If no routes match, which is the default with no configured routes, messages are delivered directly from the queue."`
274 Domain dns.Domain `sconf:"-" json:"-"`
275 ClientSettingsDNSDomain dns.Domain `sconf:"-" json:"-"`
279 Localpart string `sconf-doc:"Address-part before the @ that accepts DMARC reports. Must be non-internationalized. Recommended value: dmarc-reports."`
280 Domain string `sconf:"optional" sconf-doc:"Alternative domain for report recipient address. Can be used to receive reports for other domains. Unicode name."`
281 Account string `sconf-doc:"Account to deliver to."`
282 Mailbox string `sconf-doc:"Mailbox to deliver to, e.g. DMARC."`
284 ParsedLocalpart smtp.Localpart `sconf:"-"`
285 DNSDomain dns.Domain `sconf:"-"` // Effective domain, always set based on Domain field or Domain where this is configured.
289 PolicyID string `sconf-doc:"Policies are versioned. The version must be specified in the DNS record. If you change a policy, first change it in mox, then update the DNS record."`
290 Mode mtasts.Mode `sconf-doc:"testing, enforce or none. If set to enforce, a remote SMTP server will not deliver email to us if it cannot make a TLS connection."`
291 MaxAge time.Duration `sconf-doc:"How long a remote mail server is allowed to cache a policy. Typically 1 or several weeks."`
292 MX []string `sconf:"optional" sconf-doc:"List of server names allowed for SMTP. If empty, the configured hostname is set. Host names can contain a wildcard (*) as a leading label (matching a single label, e.g. *.example matches host.example, not sub.host.example)."`
293 // todo: parse mx as valid mtasts.Policy.MX, with dns.ParseDomain but taking wildcard into account
297 Localpart string `sconf-doc:"Address-part before the @ that accepts TLSRPT reports. Recommended value: tls-reports."`
298 Domain string `sconf:"optional" sconf-doc:"Alternative domain for report recipient address. Can be used to receive reports for other domains. Unicode name."`
299 Account string `sconf-doc:"Account to deliver to."`
300 Mailbox string `sconf-doc:"Mailbox to deliver to, e.g. TLSRPT."`
302 ParsedLocalpart smtp.Localpart `sconf:"-"`
303 DNSDomain dns.Domain `sconf:"-"` // Effective domain, always set based on Domain field or Domain where this is configured.
306type Selector struct {
307 Hash string `sconf:"optional" sconf-doc:"sha256 (default) or (older, not recommended) sha1"`
308 HashEffective string `sconf:"-"`
309 Canonicalization struct {
310 HeaderRelaxed bool `sconf-doc:"If set, some modifications to the headers (mostly whitespace) are allowed."`
311 BodyRelaxed bool `sconf-doc:"If set, some whitespace modifications to the message body are allowed."`
313 Headers []string `sconf:"optional" sconf-doc:"Headers to sign with DKIM. If empty, a reasonable default set of headers is selected."`
314 HeadersEffective []string `sconf:"-"` // Used when signing. Based on Headers from config, or the reasonable default.
315 DontSealHeaders bool `sconf:"optional" sconf-doc:"If set, don't prevent duplicate headers from being added. Not recommended."`
316 Expiration string `sconf:"optional" sconf-doc:"Period a signature is valid after signing, as duration, e.g. 72h. The period should be enough for delivery at the final destination, potentially with several hops/relays. In the order of days at least."`
317 PrivateKeyFile string `sconf-doc:"Either an RSA or ed25519 private key file in PKCS8 PEM form."`
319 ExpirationSeconds int `sconf:"-" json:"-"` // Parsed from Expiration.
320 Key crypto.Signer `sconf:"-" json:"-"` // As parsed with x509.ParsePKCS8PrivateKey.
321 Domain dns.Domain `sconf:"-" json:"-"` // Of selector only, not FQDN.
325 Selectors map[string]Selector `sconf-doc:"Emails can be DKIM signed. Config parameters are per selector. A DNS record must be created for each selector. Add the name to Sign to use the selector for signing messages."`
326 Sign []string `sconf:"optional" sconf-doc:"List of selectors that emails will be signed with."`
330 FromDomain []string `sconf:"optional" sconf-doc:"Matches if the envelope from domain matches one of the configured domains, or if the list is empty. If a domain starts with a dot, prefixes of the domain also match."`
331 ToDomain []string `sconf:"optional" sconf-doc:"Like FromDomain, but matching against the envelope to domain."`
332 MinimumAttempts int `sconf:"optional" sconf-doc:"Matches if at least this many deliveries have already been attempted. This can be used to attempt sending through a smarthost when direct delivery has failed for several times."`
333 Transport string `sconf:"The transport used for delivering the message that matches requirements of the above fields."`
335 // todo future: add ToMX, where we look up the MX record of the destination domain and check (the first, any, all?) mx host against the values in ToMX.
337 FromDomainASCII []string `sconf:"-"`
338 ToDomainASCII []string `sconf:"-"`
339 ResolvedTransport Transport `sconf:"-" json:"-"`
342// todo: move RejectsMailbox to store.Mailbox.SpecialUse, possibly with "X" prefix?
345 Domain string `sconf-doc:"Default domain for account. Deprecated behaviour: If a destination is not a full address but only a localpart, this domain is added to form a full address."`
346 Description string `sconf:"optional" sconf-doc:"Free form description, e.g. full name or alternative contact info."`
347 FullName string `sconf:"optional" sconf-doc:"Full name, to use in message From header when composing messages in webmail. Can be overridden per destination."`
348 Destinations map[string]Destination `sconf-doc:"Destinations, keys are email addresses (with IDNA domains). If the address is of the form '@domain', i.e. with localpart missing, it serves as a catchall for the domain, matching all messages that are not explicitly configured. Deprecated behaviour: If the address is not a full address but a localpart, it is combined with Domain to form a full address."`
350 Period time.Duration `sconf-doc:"How long unique values are accepted after generating, e.g. 12h."` // todo: have a reasonable default for this?
351 } `sconf:"optional" sconf-doc:"If configured, messages classified as weakly spam are rejected with instructions to retry delivery, but this time with a signed token added to the subject. During the next delivery attempt, the signed token will bypass the spam filter. Messages with a clear spam signal, such as a known bad reputation, are rejected/delayed without a signed token."`
352 QuotaMessageSize int64 `sconf:"optional" sconf-doc:"Default maximum total message size for the account, overriding any globally configured maximum size if non-zero. A negative value can be used to have no limit in case there is a limit by default. Attempting to add new messages beyond the maximum size will result in an error. Useful to prevent a single account from filling storage."`
353 RejectsMailbox string `sconf:"optional" sconf-doc:"Mail that looks like spam will be rejected, but a copy can be stored temporarily in a mailbox, e.g. Rejects. If mail isn't coming in when you expect, you can look there. The mail still isn't accepted, so the remote mail server may retry (hopefully, if legitimate), or give up (hopefully, if indeed a spammer). Messages are automatically removed from this mailbox, so do not set it to a mailbox that has messages you want to keep."`
354 KeepRejects bool `sconf:"optional" sconf-doc:"Don't automatically delete mail in the RejectsMailbox listed above. This can be useful, e.g. for future spam training."`
355 AutomaticJunkFlags struct {
356 Enabled bool `sconf-doc:"If enabled, flags will be set automatically if they match a regular expression below. When two of the three mailbox regular expressions are set, the remaining one will match all unmatched messages. Messages are matched in the order specified and the search stops on the first match. Mailboxes are lowercased before matching."`
357 JunkMailboxRegexp string `sconf:"optional" sconf-doc:"Example: ^(junk|spam)."`
358 NeutralMailboxRegexp string `sconf:"optional" sconf-doc:"Example: ^(inbox|neutral|postmaster|dmarc|tlsrpt|rejects), and you may wish to add trash depending on how you use it, or leave this empty."`
359 NotJunkMailboxRegexp string `sconf:"optional" sconf-doc:"Example: .* or an empty string."`
360 } `sconf:"optional" sconf-doc:"Automatically set $Junk and $NotJunk flags based on mailbox messages are delivered/moved/copied to. Email clients typically have too limited functionality to conveniently set these flags, especially $NonJunk, but they can all move messages to a different mailbox, so this helps them."`
361 JunkFilter *JunkFilter `sconf:"optional" sconf-doc:"Content-based filtering, using the junk-status of individual messages to rank words in such messages as spam or ham. It is recommended you always set the applicable (non)-junk status on messages, and that you do not empty your Trash because those messages contain valuable ham/spam training information."` // todo: sane defaults for junkfilter
362 MaxOutgoingMessagesPerDay int `sconf:"optional" sconf-doc:"Maximum number of outgoing messages for this account in a 24 hour window. This limits the damage to recipients and the reputation of this mail server in case of account compromise. Default 1000."`
363 MaxFirstTimeRecipientsPerDay int `sconf:"optional" sconf-doc:"Maximum number of first-time recipients in outgoing messages for this account in a 24 hour window. This limits the damage to recipients and the reputation of this mail server in case of account compromise. Default 200."`
364 Routes []Route `sconf:"optional" sconf-doc:"Routes for delivering outgoing messages through the queue. Each delivery attempt evaluates these account routes, domain routes and finally global routes. The transport of the first matching route is used in the delivery attempt. If no routes match, which is the default with no configured routes, messages are delivered directly from the queue."`
366 DNSDomain dns.Domain `sconf:"-"` // Parsed form of Domain.
367 JunkMailbox *regexp.Regexp `sconf:"-" json:"-"`
368 NeutralMailbox *regexp.Regexp `sconf:"-" json:"-"`
369 NotJunkMailbox *regexp.Regexp `sconf:"-" json:"-"`
372type JunkFilter struct {
373 Threshold float64 `sconf-doc:"Approximate spaminess score between 0 and 1 above which emails are rejected as spam. Each delivery attempt adds a little noise to make it slightly harder for spammers to identify words that strongly indicate non-spaminess and use it to bypass the filter. E.g. 0.95."`
377type Destination struct {
378 Mailbox string `sconf:"optional" sconf-doc:"Mailbox to deliver to if none of Rulesets match. Default: Inbox."`
379 Rulesets []Ruleset `sconf:"optional" sconf-doc:"Delivery rules based on message and SMTP transaction. You may want to match each mailing list by SMTP MailFrom address, VerifiedDomain and/or List-ID header (typically <listname.example.org> if the list address is listname@example.org), delivering them to their own mailbox."`
380 FullName string `sconf:"optional" sconf-doc:"Full name to use in message From header when composing messages coming from this address with webmail."`
382 DMARCReports bool `sconf:"-" json:"-"`
383 HostTLSReports bool `sconf:"-" json:"-"`
384 DomainTLSReports bool `sconf:"-" json:"-"`
387// Equal returns whether d and o are equal, only looking at their user-changeable fields.
388func (d Destination) Equal(o Destination) bool {
389 if d.Mailbox != o.Mailbox || len(d.Rulesets) != len(o.Rulesets) {
392 for i, rs := range d.Rulesets {
393 if !rs.Equal(o.Rulesets[i]) {
401 SMTPMailFromRegexp string `sconf:"optional" sconf-doc:"Matches if this regular expression matches (a substring of) the SMTP MAIL FROM address (not the message From-header). E.g. '^user@example\\.org$'."`
402 VerifiedDomain string `sconf:"optional" sconf-doc:"Matches if this domain matches an SPF- and/or DKIM-verified (sub)domain."`
403 HeadersRegexp map[string]string `sconf:"optional" sconf-doc:"Matches if these header field/value regular expressions all match (substrings of) the message headers. Header fields and valuees are converted to lower case before matching. Whitespace is trimmed from the value before matching. A header field can occur multiple times in a message, only one instance has to match. For mailing lists, you could match on ^list-id$ with the value typically the mailing list address in angled brackets with @ replaced with a dot, e.g. <name\\.lists\\.example\\.org>."`
404 // todo: add a SMTPRcptTo check, and MessageFrom that works on a properly parsed From header.
406 // todo: once we implement ARC, we can use dkim domains that we cannot verify but that the arc-verified forwarding mail server was able to verify.
407 IsForward bool `sconf:"optional" sconf-doc:"Influences spam filtering only, this option does not change whether a message matches this ruleset. Can only be used together with SMTPMailFromRegexp and VerifiedDomain. SMTPMailFromRegexp must be set to the address used to deliver the forwarded message, e.g. '^user(|\\+.*)@forward\\.example$'. Changes to junk analysis: 1. Messages are not rejects for failing a DMARC policy, because a legitimate forwarded message without valid/intact/aligned DKIM signature would be rejected because any verified SPF domain will be 'unaligned', of the forwarding mail server. 2. The sending mail server IP address, and sending EHLO and MAIL FROM domains and matching DKIM domain aren't used in future reputation-based spam classifications (but other verified DKIM domains are) because the forwarding server is not a useful spam signal for future messages."`
408 ListAllowDomain string `sconf:"optional" sconf-doc:"Influences spam filtering only, this option does not change whether a message matches this ruleset. If this domain matches an SPF- and/or DKIM-verified (sub)domain, the message is accepted without further spam checks, such as a junk filter or DMARC reject evaluation. DMARC rejects should not apply for mailing lists that are not configured to rewrite the From-header of messages that don't have a passing DKIM signature of the From-domain. Otherwise, by rejecting messages, you may be automatically unsubscribed from the mailing list. The assumption is that mailing lists do their own spam filtering/moderation."`
409 AcceptRejectsToMailbox string `sconf:"optional" sconf-doc:"Influences spam filtering only, this option does not change whether a message matches this ruleset. If a message is classified as spam, it isn't rejected during the SMTP transaction (the normal behaviour), but accepted during the SMTP transaction and delivered to the specified mailbox. The specified mailbox is not automatically cleaned up like the account global Rejects mailbox, unless set to that Rejects mailbox."`
411 Mailbox string `sconf-doc:"Mailbox to deliver to if this ruleset matches."`
413 SMTPMailFromRegexpCompiled *regexp.Regexp `sconf:"-" json:"-"`
414 VerifiedDNSDomain dns.Domain `sconf:"-"`
415 HeadersRegexpCompiled [][2]*regexp.Regexp `sconf:"-" json:"-"`
416 ListAllowDNSDomain dns.Domain `sconf:"-"`
419// Equal returns whether r and o are equal, only looking at their user-changeable fields.
420func (r Ruleset) Equal(o Ruleset) bool {
421 if r.SMTPMailFromRegexp != o.SMTPMailFromRegexp || r.VerifiedDomain != o.VerifiedDomain || r.IsForward != o.IsForward || r.ListAllowDomain != o.ListAllowDomain || r.AcceptRejectsToMailbox != o.AcceptRejectsToMailbox || r.Mailbox != o.Mailbox {
424 if !reflect.DeepEqual(r.HeadersRegexp, o.HeadersRegexp) {
431 CertFile string `sconf-doc:"Certificate including intermediate CA certificates, in PEM format."`
432 KeyFile string `sconf-doc:"Private key for certificate, in PEM format. PKCS8 is recommended, but PKCS1 and EC private keys are recognized as well."`
436 ACME string `sconf:"optional" sconf-doc:"Name of provider from top-level configuration to use for ACME, e.g. letsencrypt."`
437 KeyCerts []KeyCert `sconf:"optional" sconf-doc:"Keys and certificates to use for this listener. The files are opened by the privileged root process and passed to the unprivileged mox process, so no special permissions are required on the files. If the private key will not be replaced when refreshing certificates, also consider adding the private key to HostPrivateKeyFiles and configuring DANE TLSA DNS records."`
438 MinVersion string `sconf:"optional" sconf-doc:"Minimum TLS version. Default: TLSv1.2."`
439 HostPrivateKeyFiles []string `sconf:"optional" sconf-doc:"Private keys used for ACME certificates. Specified explicitly so DANE TLSA DNS records can be generated, even before the certificates are requested. DANE is a mechanism to authenticate remote TLS certificates based on a public key or certificate specified in DNS, protected with DNSSEC. DANE is opportunistic and attempted when delivering SMTP with STARTTLS. The private key files must be in PEM format. PKCS8 is recommended, but PKCS1 and EC private keys are recognized as well. Only RSA 2048 bit and ECDSA P-256 keys are currently used. The first of each is used when requesting new certificates through ACME."`
441 Config *tls.Config `sconf:"-" json:"-"` // TLS config for non-ACME-verification connections, i.e. SMTP and IMAP, and not port 443.
442 ACMEConfig *tls.Config `sconf:"-" json:"-"` // TLS config that handles ACME verification, for serving on port 443.
443 HostPrivateRSA2048Keys []crypto.Signer `sconf:"-" json:"-"` // Private keys for new TLS certificates for listener host name, for new certificates with ACME, and for DANE records.
444 HostPrivateECDSAP256Keys []crypto.Signer `sconf:"-" json:"-"`
447type WebHandler struct {
448 LogName string `sconf:"optional" sconf-doc:"Name to use in logging and metrics."`
449 Domain string `sconf-doc:"Both Domain and PathRegexp must match for this WebHandler to match a request. Exactly one of WebStatic, WebRedirect, WebForward must be set."`
450 PathRegexp string `sconf-doc:"Regular expression matched against request path, must always start with ^ to ensure matching from the start of the path. The matching prefix can optionally be stripped by WebForward. The regular expression does not have to end with $."`
451 DontRedirectPlainHTTP bool `sconf:"optional" sconf-doc:"If set, plain HTTP requests are not automatically permanently redirected (308) to HTTPS. If you don't have a HTTPS webserver configured, set this to true."`
452 Compress bool `sconf:"optional" sconf-doc:"Transparently compress responses (currently with gzip) if the client supports it, the status is 200 OK, no Content-Encoding is set on the response yet and the Content-Type of the response hints that the data is compressible (text/..., specific application/... and .../...+json and .../...+xml). For static files only, a cache with compressed files is kept."`
453 WebStatic *WebStatic `sconf:"optional" sconf-doc:"Serve static files."`
454 WebRedirect *WebRedirect `sconf:"optional" sconf-doc:"Redirect requests to configured URL."`
455 WebForward *WebForward `sconf:"optional" sconf-doc:"Forward requests to another webserver, i.e. reverse proxy."`
457 Name string `sconf:"-"` // Either LogName, or numeric index if LogName was empty. Used instead of LogName in logging/metrics.
458 DNSDomain dns.Domain `sconf:"-"`
459 Path *regexp.Regexp `sconf:"-" json:"-"`
462// Equal returns if wh and o are equal, only looking at fields in the configuration file, not the derived fields.
463func (wh WebHandler) Equal(o WebHandler) bool {
464 clean := func(x WebHandler) WebHandler {
466 x.DNSDomain = dns.Domain{}
478 if (wh.WebStatic == nil) != (o.WebStatic == nil) || (wh.WebRedirect == nil) != (o.WebRedirect == nil) || (wh.WebForward == nil) != (o.WebForward == nil) {
481 if wh.WebStatic != nil {
482 return reflect.DeepEqual(wh.WebStatic, o.WebStatic)
484 if wh.WebRedirect != nil {
485 return wh.WebRedirect.equal(*o.WebRedirect)
487 if wh.WebForward != nil {
488 return wh.WebForward.equal(*o.WebForward)
493type WebStatic struct {
494 StripPrefix string `sconf:"optional" sconf-doc:"Path to strip from the request URL before evaluating to a local path. If the requested URL path does not start with this prefix and ContinueNotFound it is considered non-matching and next WebHandlers are tried. If ContinueNotFound is not set, a file not found (404) is returned in that case."`
495 Root string `sconf-doc:"Directory to serve files from for this handler. Keep in mind that relative paths are relative to the working directory of mox."`
496 ListFiles bool `sconf:"optional" sconf-doc:"If set, and a directory is requested, and no index.html is present that can be served, a file listing is returned. Results in 403 if ListFiles is not set. If a directory is requested and the URL does not end with a slash, the response is a redirect to the path with trailing slash."`
497 ContinueNotFound bool `sconf:"optional" sconf-doc:"If a requested URL does not exist, don't return a file not found (404) response, but consider this handler non-matching and continue attempts to serve with later WebHandlers, which may be a reverse proxy generating dynamic content, possibly even writing a static file for a next request to serve statically. If ContinueNotFound is set, HTTP requests other than GET and HEAD do not match. This mechanism can be used to implement the equivalent of 'try_files' in other webservers."`
498 ResponseHeaders map[string]string `sconf:"optional" sconf-doc:"Headers to add to the response. Useful for cache-control, content-type, etc. By default, Content-Type headers are automatically added for recognized file types, unless added explicitly through this setting. For directory listings, a content-type header is skipped."`
501type WebRedirect struct {
502 BaseURL string `sconf:"optional" sconf-doc:"Base URL to redirect to. The path must be empty and will be replaced, either by the request URL path, or by OrigPathRegexp/ReplacePath. Scheme, host, port and fragment stay intact, and query strings are combined. If empty, the response redirects to a different path through OrigPathRegexp and ReplacePath, which must then be set. Use a URL without scheme to redirect without changing the protocol, e.g. //newdomain/. If a redirect would send a request to a URL with the same scheme, host and path, the WebRedirect does not match so a next WebHandler can be tried. This can be used to redirect all plain http traffic to https."`
503 OrigPathRegexp string `sconf:"optional" sconf-doc:"Regular expression for matching path. If set and path does not match, a 404 is returned. The HTTP path used for matching always starts with a slash."`
504 ReplacePath string `sconf:"optional" sconf-doc:"Replacement path for destination URL based on OrigPathRegexp. Implemented with Go's Regexp.ReplaceAllString: $1 is replaced with the text of the first submatch, etc. If both OrigPathRegexp and ReplacePath are empty, BaseURL must be set and all paths are redirected unaltered."`
505 StatusCode int `sconf:"optional" sconf-doc:"Status code to use in redirect, e.g. 307. By default, a permanent redirect (308) is returned."`
507 URL *url.URL `sconf:"-" json:"-"`
508 OrigPath *regexp.Regexp `sconf:"-" json:"-"`
511func (wr WebRedirect) equal(o WebRedirect) bool {
516 return reflect.DeepEqual(wr, o)
519type WebForward struct {
520 StripPath bool `sconf:"optional" sconf-doc:"Strip the matching WebHandler path from the WebHandler before forwarding the request."`
521 URL string `sconf-doc:"URL to forward HTTP requests to, e.g. http://127.0.0.1:8123/base. If StripPath is false the full request path is added to the URL. Host headers are sent unmodified. New X-Forwarded-{For,Host,Proto} headers are set. Any query string in the URL is ignored. Requests are made using Go's net/http.DefaultTransport that takes environment variables HTTP_PROXY and HTTPS_PROXY into account. Websocket connections are forwarded and data is copied between client and backend without looking at the framing. The websocket 'version' and 'key'/'accept' headers are verified during the handshake, but other websocket headers, including 'origin', 'protocol' and 'extensions' headers, are not inspected and the backend is responsible for verifying/interpreting them."`
522 ResponseHeaders map[string]string `sconf:"optional" sconf-doc:"Headers to add to the response. Useful for adding security- and cache-related headers."`
524 TargetURL *url.URL `sconf:"-" json:"-"`
527func (wf WebForward) equal(o WebForward) bool {
530 return reflect.DeepEqual(wf, o)