A Postfix configuration question

[Tom H]

On Mon, Nov 23, 2015 at 11:08 PM, Colin Law <clanlaw at gmail.com> wrote:
>
> I have set up Postfix for the first time, on a server, setting
> mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
> smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated
> defer_unauth_destination
>
> and every couple of hours I am seeing, in syslog
> Nov 23 20:38:06 10955 postfix/smtpd[21510]: warning: inet_protocols:
> disabling IPv6 name/address support: Address family not supported by
> protocol
> Nov 23 20:38:06 10955 postfix/proxymap[21511]: warning:
> inet_protocols: disabling IPv6 name/address support: Address family
> not supported by protocol
> Nov 23 20:38:06 10955 postfix/smtpd[21510]: warning: hostname
> co.la-paz.az.us does not resolve to address 24.121.225.29
> Nov 23 20:38:06 10955 postfix/smtpd[21510]: connect from unknown[24.121.225.29]
> Nov 23 20:38:06 10955 postfix/anvil[21512]: warning: inet_protocols:
> disabling IPv6 name/address support: Address family not supported by
> protocol
> Nov 23 20:38:07 10955 postfix/smtpd[21510]: disconnect from
> unknown[24.121.225.29]
>
> Is this just someone trying to relay through me, and do I need to do
> anything about it?

1) Re " warning: inet_protocols: disabling IPv6 name/address support:
Address family not supported by protocol"

You mustn't have ipv6 enabled. The warning'll go away if you change
mynetworks and inet_protocols (the latter might even be enough) to be
ipv4 only.

2) Re "postfix/smtpd" messages

You have "mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128"
so you must've chosen the "local only" debconf setting when installing
postfix. Did you then edit "/etc/postfix/main.cf"?

What's the output of
ss -ntl
cat /etc/hosts
cat /etc/hostname
postconf | grep -E '^inet|^my'