sendmail config help

[Anton Shterenlikht]

>From: Matthew Seaman <m.seaman at infracaninophile.co.uk>
>
>On 2016/01/05 11:05, Anton Shterenlikht wrote:
>> The best I can get is:
>>=20
>> 553 5.3.5 z.com. config error: mail loops back to me (MX problem?)
>> 554 5.3.5 Local configuration error
>
>This indicates that although the MX records in the DNS point to your
>machine to handle the e-mail for z.com, the machine's sendmail
>configuration doesn't state that it should handle the final delivery for
>z.com messages.
>
>You need to add z.com to the file /etc/mail/local-host-names and then
>bounce sendmail.  What this does is add z.com to sendmail's class w --
>the list of addresses which this instance of sendmail 'owns.'

Matthew, thank you, that solved the problem.

>Personally, I'd name the mail server as 'smtp.z.com' and use an MX
>record to direct the mail to it.  That's pretty standard and it will
>help avoid your messages getting classed as spam.

Sorry, I don't understand this fully.

After I set smtp.z.com in MX record,
do I need to change anything on the server side
for this to work?

I naively thought that using smtp.z.com makes
sense only if it refers to physically diffent
host than z.com. Am I wrong?

Sorry for taking your time.
Perhaps you can point to a good background
reading on this. I'm lost in multitude of
advice on the net.

Anton