# How to determine SMTP setting from Exim?

**URL:** <https://meta.discourse.org/t/how-to-determine-smtp-setting-from-exim/53941>\
**Category:** Self-hosting\
**Created:** [2016 年12 月 7 日 22:24 UTC](https://meta.discourse.org/t/how-to-determine-smtp-setting-from-exim/53941 "2016-12-07T22:24:59Z")\
**Posts on this page:** 1\
**Showing post:** 5

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作者： ![elijah](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/elijah/32/104055_2.png) [@elijah](https://meta.discourse.org/u/elijah)\
发布日期： [2016 年12 月 8 日 20:39 UTC](https://meta.discourse.org/t/how-to-determine-smtp-setting-from-exim/53941/5 "2016-12-08T20:39:16Z")

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I don’t feel like I’m certain in my answer, because I don’t understand your set up (and I’m not expert in this). BUT that said, let me explain further.

My environment has a robust local mail system. My environment has countless small VMs that are all pre-configured to have local mail forward appropriately.

When I set up Discourse, I installed (ran `discourse-setup`) on `web-forum-1.$colo_name.$dotcom` and configured it to use `mailhost.internal.$dotcom` for SMTP host and `25` for SMTP port, with no username or password. But it would have worked to use `web-forum-1.$colo_name.$dotcom`, too, because `telnet localhost 25` works on that box, and Postfix there is configured to relay through `mailhost.internal.$dotcom`. That is a CNAME for one of the Exchange (eww, ick, says my inner Unix guru) servers, which does spam checks and routing to internal or external addresses.

(Separately I have the network configured to map the external hostname of `discussion.$dotcom` to the internal server `web-forum-1.$colo_name.$dotcom` because I want the service name to be independent of the backend.)

So going back to your question, since it seems you have a working Exim set up on your linux box, the Docker container should probably be configured to talk to that local Exim instance. The hostname will be the name of the “linux box running Exim” and the port 25, or 587, or one of the other two. And no authentication values.

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