X-Git-Url: https://git.exim.org/exim-website.git/blobdiff_plain/6bc094771cb3ac2e80fb8669432dde5cf3740c8d..8e4b09729f6a0cefe6c78bb38da734d11aa588ad:/howto/relay.html?ds=sidebyside diff --git a/howto/relay.html b/howto/relay.html deleted file mode 100644 index 3ff1a7b..0000000 --- a/howto/relay.html +++ /dev/null @@ -1,82 +0,0 @@ - - - - HOWTO - Preventing Relaying - - - -

HOWTO - Preventing Relaying

- -

Many people want to get a free ride from your system by using - it for relaying their mail. This can be due to them being - corrupt and wishing to let you take the rap for relaying their - junk, or them being lazy and unable to make their own systems - work. In any case this is a theft of service and needs to be - stopped.

- -

Exim v4.x Relay Control

- -

Exim v4.x has completely different and considerably more - flexible mail policy controls than earlier versions. The - documentation is also considerable more complete and the default - configuration file has a well commented section on relay control - (in the RCPT TO ACL. You should instead read the - specification section on Access - Control Lists.

- -

Exim v3.x Relay Configuration Options

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These are fully detailed in the Exim Specification Document. The specific - section on relaying is here

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    -
  1. Firstly you need to specify the local mail domains as - tightly as possible. local_domains should only cover - domains that really are local - this is relevant since exim - allows any sender to mail to these domains (since you have - told exim those domains are local you are not actually - relaying by sending to them.
    2. - -
  2. Any domains that are not finally handled by the local exim, - but can legitmately be relayed through (ie domains you act as - backup MX for) should be specified in the - relay_domains, although a short cut for doing this is - setting relay_domains_include_local_mx which can be - used to abuse your mail server by adding MXes pointing at you, - but raises the bar so much higher than it is normally good - enough.
    3. - -
  3. You probably want to be able to relay out from local - machines on the same network - be careful here since any open - machine on your network could be used to do unauthorised - relaying. The control of hosts that can relay is done with the - host_accept_relay - option.
    4. - -
- -

The standard settings for a workstation, allowing relaying - through the loopback (since packages such as MH post mail this - way), would be:-

-
-relay_domains =
-no_relay_domains_include_local_mx
-no_relay_match_host_or_sender
-host_accept_relay = 127.0.0.1/8
-
-

this is actually the default settings other than that for - host_accept_relay.

- -

The information to do more complicated manipulations can be - found in the specification document and is outside the scope of - this note.

-
-
Nigel Metheringham
- -

$Cambridge$

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