A Postfix configuration question

[Colin Law]

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?

Colin