[TriLUG] Postfix Problems - DNS resolution different?

[B. Evans]

I recently installed RedHat 8 on another machine.  The previous box had 
RedHat 7.3 and postfix worked right out of the box.  The new install is 
throwing the errors below in the log (/var/log/maillog).  The security 
is good, it accepts mail from my subnet.  But the log indicates to me 
that DNS is hosed.  DNS & resolv.conf on the system seems to work fine, 
pings and browsing on the machine work perfectly.  Any idea what to check?


Jan 15 09:40:42 Ellsworth postfix/postfix-script: starting the Postfix 
mail system
Jan 15 09:40:43 Ellsworth postfix/master[991]: daemon started
Jan 15 09:41:53 Ellsworth postfix/smtpd[997]: connect from 
unknown[9.27.134.220]
Jan 15 09:41:53 Ellsworth postfix/smtpd[997]: B66563EEEB: 
client=unknown[9.27.134.220]
Jan 15 09:41:53 Ellsworth postfix/cleanup[998]: B66563EEEB: 
message-id=<3E257502.80800 at bellsouth.net>
Jan 15 09:41:54 Ellsworth postfix/nqmgr[995]: B66563EEEB: 
from=<bpevans at bellsouth.net>, size=976, nrcpt=1 (queue active)
Jan 15 09:41:54 Ellsworth postfix/smtpd[997]: disconnect from 
unknown[9.27.134.220]
Jan 15 09:41:54 Ellsworth postfix/smtp[1000]: B66563EEEB: 
to=<bpevans at bellsouth.net>, relay=none, delay=1, status=deferred (Name 
service error for bellsouth.net: Host not found, try again)

-bp