[CentOS] sendmail

[Stephen John Smoogen]

On 2 October 2017 at 18:03, Larry Martell <larry.martell at gmail.com> wrote:
> On Mon, Oct 2, 2017 at 5:29 PM, Stephen John Smoogen <smooge at gmail.com> wrote:
>> On 2 October 2017 at 17:21, Larry Martell <larry.martell at gmail.com> wrote:
>>> I an running CentOS7 in a docker container. I need to send email from
>>> that container so I installed sendmail and then I run:
>>>
>>> m4 /etc/mail/sendmail.mc > /etc/mail/sendmail.cf` and when I try and
>>> send mail it fails with:
>>>
>>> larry.martll at gmail.com... Connecting to [127.0.0.1] via relay...
>>> larry.martll at gmail.com... Deferred: Connection refused by [127.0.0.1]
>>>
>>> Anyone know how I can configure sendmail so that I can send mail?
>>
>> Does this help any?
>>
>> https://stackoverflow.com/questions/26215021/configure-sendmail-inside-a-docker-container
>
> That post is a bit overwhelming. It has 20+ answers and all are different.
>
> I have another container running debian buster and in there I do"
>
> yes yes | sendmailconfig
>
> and then I can send mail. But I don't see sendmailconfig in CentOS7.
> Is there an equivalent?

Sendmail is not the standard email server for EL7 so I am a bit rusty
here.  The item that caught my attention was the following:

------
I figured out a way myself, although not the most elegant solution. I
configured the sendmail inside my docker so as to Relay the request
via host's ip. Add the following line to the file "/etc/mail/access

Connect:<host_ip_here>          RELAY
Also, in the host as well as docker, comment out the following line in
the file "/etc/mail/sendmail.mc" by prefixing it with "dnl #" and
suffixing with "dnl".

DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
I passed the host ip as an environment variable to the docker
container, so that it is configurable. Now the docker's sendmail will
relay it's sendmail's smtp request via host machine.

-------

Beyond that I am not going to be much help as I have not had much
experience with docker.

-- 
Stephen J Smoogen.