Postfix misconfiguration or DNS issue

willcastle · 02-16-2011, 09:01 PM

Hi,

Recently I noticed that I am not receiving new emails and at the same time cannot send mails.

Please tell me what this means.
This was the output of tail -f /var/log/maillog:

Quote:

Feb 17 10:54:03 porto postfix/smtp[6727]: AAE024936F7: to=<myemail@yahoo.com>, relay=none, delay=3137, delays=3117/0.01/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=yahoo.com type=MX: Host not found, try again)

Thank you and have a great day to you all..

Berhanie · 02-16-2011, 11:49 PM

Quote:

Please tell me what this means.

it means that postfix cannot resolve yahoo.com. you might try running the following
command on the machine running postfix to see if you can query dns manually:

Code:

dig yahoo.com mx

willcastle · 02-17-2011, 12:29 AM

Quote:

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> yahoo.com mx
;; global options: printcmd
;; connection timed out; no servers could be reached

Hi,

I think I can't send and receive emails from/to anyone. I've already sent test emails.

Thank you and have a great day.

willcastle · 02-17-2011, 12:31 AM

Hi,

I've already checked the connections on the server and it seems okay. However I can't ping any IP address from the postfix machine.

Berhanie · 02-17-2011, 07:46 AM

Quote:

However I can't ping any IP address from the postfix machine.

ok, so this isn't a postfix nor a dns issue. maybe you should check your IP configuration
(address, default route). is this a fresh install, or is this a sudden problem with
a working server?

willcastle · 02-17-2011, 08:01 PM

Hi,

I noticed that when I ping LAN addresses it has no problem, however I can't ping outside addresses like the IP of yahoo.com. I think it's a sudden problem. Because last week it is still working fine. Thank you for your help.

Berhanie · 02-17-2011, 08:12 PM

you might double-check that you can ping your router, and that your default route points to the router's IP address (e.g. by looking at the output of "ip route ls" on the postfix machine). if everything looks good, you can try a traceroute to something outside your LAN. if the traceroute stops at the router, maybe it's a problem with the router.

willcastle · 02-17-2011, 08:25 PM

Code:

ip route ls

This was the output:

Code:

192.168.101.0/24 dev eth1  proto kernel  scope link  src 192.168.101.5
169.254.0.0/16 dev eth1  scope link
default via 192.168.101.1 dev eth1

I've done traceroute and it's not successful. I am confused, because the postfix machine is at the same the web server. I can view our website from the outside. I can't ping the router which is 122.54.172.51.

Berhanie · 02-17-2011, 11:30 PM

you should be able to ping the LAN-facing side of the router, which according to the output is 192.168.101.1. as to why you can't ping anything outside your LAN, you can start by looking at the firewall rules on the server and the router.

willcastle · 02-18-2011, 12:12 AM

Hi,

Now I'm really confuse. I thought that it is a hardware problem I replaced the network card but it is still the same. I thought if I replace the card it will be alright but I guess I'm wrong.

Code:

192.168.101.0/24 dev eth1  proto kernel  scope link  src 192.168.101.5
169.254.0.0/16 dev eth1  scope link

Now this is the output of ip route ls.