Section: User Commands (1)
Updated: local
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emailrelay - e-mail transfer agent and proxy  


emailrelay [OPTIONS]

emailrelay --as-server

emailrelay --as-client server-address

emailrelay --as-proxy server-address  


emailrelay is a simple SMTP proxy and store-and-forward message transfer agent. It does store-and-forward mail relay to a fixed next-hop server, without any routing.

It runs in two main modes: a storage daemon (--as-server) and a forwarding agent (--as-client). The storage daemon is an SMTP server which stores e-mail messages in a local spool directory. The forwarding agent acts as an SMTP client sending the spooled e-mail messages on to the next SMTP server in the chain.

It can also run in a third mode, as a proxy server (--as-proxy). In this mode all messages are forwarded immediately to the next-hop server. Messages are only fully accepted from the sender once they have been successfully delivered to the next-hop server.  


-a, --admin <admin-port>
Enables the administration interface and specifies its listening port number.
-Q, --admin-terminate
Enables the terminate command on the admin interface.
-A, --anonymous
Disables the smtp vrfy command and sends less verbose smtp responses.
-q, --as-client <host:port>
Runs as a client, forwarding spooled mail to <host>: equivalent to --log --no-syslog --no-daemon --dont-serve --forward --forward-to.
-y, --as-proxy <host:port>
Runs as a proxy: equivalent to --log --close-stderr --immediate --forward-to.
-d, --as-server
Runs as a server: equivalent to --log --close-stderr.
-C, --client-auth <file>
Enables smtp authentication with the remote server, using the given secrets file.
-Y, --client-filter <program>
Specifies an external program to process messages when they are forwarded.
-j, --client-tls
Enables tls/ssl layer for smtp client (if openssl built in).
-e, --close-stderr
Closes the standard error stream soon after start-up.
-U, --connection-timeout <time>
Sets the timeout (in seconds) when connecting to a remote server (default is 40).
-g, --debug
Generates debug-level logging if compiled-in.
-D, --domain <fqdn>
Sets an override for the host's fully qualified domain name.
-x, --dont-serve
Disables acting as a server on any port (part of --as-client and usually used with --forward).
-z, --filter <program>
Specifies an external program to process messages as they are stored.
-W, --filter-timeout <time>
Sets the timeout (in seconds) for running the --filter processor (default is 300).
-f, --forward
Forwards stored mail on startup (requires --forward-to).
-o, --forward-to <host:port>
Specifies the remote smtp server (required by --forward, --poll, --immediate and --admin).
-h, --help
Displays help text and exits.
-m, --immediate
Enables immediate forwarding of messages as soon as they are received (requires --forward-to).
-I, --interface <ip-address>
Defines the listening interface for incoming connections.
-l, --log
Writes log information on standard error and syslog.
-L, --log-time
Adds a timestamp to the logging output.
-t, --no-daemon
Does not detach from the terminal.
-X, --no-smtp
Disables listening for smtp connections (usually used with --admin or --pop).
-n, --no-syslog
Disables syslog output (always overridden by --syslog).
-i, --pid-file <pid-file>
Defines a file for storing the daemon process-id.
-O, --poll <period>
Enables polling of the spool directory for messages to be forwarded with the specified period (requires --forward-to).
-B, --pop
Enables the pop server.
-F, --pop-auth <file>
Defines the pop server secrets file (default is /etc/emailrelay.auth).
-J, --pop-by-name
Modifies the pop spool directory according to the user name (requires --pop).
-G, --pop-no-delete
Disables message deletion via pop (requires --pop).
-E, --pop-port <port>
Specifies the pop listening port number (requires --pop).
-p, --port <port>
Specifies the smtp listening port number.
-w, --prompt-timeout <time>
Sets the timeout (in seconds) for getting an initial prompt from the server.
-r, --remote-clients
Allows remote clients to connect.
-T, --response-timeout <time>
Sets the response timeout (in seconds) when talking to a remote server (default is 1800).
-S, --server-auth <file>
Enables authentication of remote clients, using the given secrets file.
-K, --server-tls <pem-file>
Enables tls/ssl layer for smtp server using the given openssl certificate file (if openssl built in).
-M, --size <bytes>
Limits the size of submitted messages.
-s, --spool-dir <dir>
Specifies the spool directory (default is /var/spool/emailrelay).
-k, --syslog
Forces syslog output if logging is enabled (overrides --no-syslog).
-u, --user <username>
Names the effective user to switch to if started as root (default is daemon).
-v, --verbose
Generates more verbose output (works with --help and --log).
-Z, --verifier <program>
Specifies an external program for address verification.
-V, --version
Displays version information and exits.


GNU style...

FHS style...


E-MailRelay user guide, .
E-MailRelay reference, .
emailrelay-submit(1), emailrelay-passwd(1),  


Graeme Walker,




This document was created by man2html, using the manual pages.