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dns suddenly stopped resolving names - now no email [solved]

Offline robf355

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The problem was caused by a bad backup script, which filled the disk up.

Hi
I went away for the weekend, whilst away, suddenly email stopped working. no emails could be sent or received. I could still access the http pages and the imap section still worked ok.
When I returned today (monday) I checked the server, rebooted in case something had crashed, but still the same issue. I can't ping any host from the server, but i can ping an external or internal ip address.
I tried manually adding a dns server address to the server config but i still get host lookup failed when i try a nslookup or ping. If i add in the dnsserver address to the nslookup command I get a correct lookup, i.e.
nslookup www.bbc.co.uk fails with
;; connection timed out; trying next origin
;; connection timed out; no servers could be reached

whereas
nslookup www.bbc.co.uk 194.168.4.123
Server:         194.168.4.123
Address:        194.168.4.123#53

Non-authoritative answer:
www.bbc.co.uk   canonical name = www.bbc.net.uk.
Name:   www.bbc.net.uk
Address: 212.58.246.93
Name:   www.bbc.net.uk
Address: 212.58.244.69

All the other computers on the network can access the internet without any problems, they all use the same dns. Can any one point me in a direction of where to look, I've checked /var/log/messages and there wasn't anything unusual, I have noticed that when i try to login to the console after entering the username it takes about 5 seconds for the password prompt to appear, it didn't used to take that long.

One other thing is that there are about 20 instances of qpsmtpd-forkser running, but /etc/init.d/qpsmtpd-forkserver status reports process not running!

Regards
Rob Carter
« Last Edit: June 11, 2018, 05:43:23 PM by robf355 »

Offline larieu

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Re: dns suddenly stopped resolving names - now no email [solved]
« Reply #1 on: June 11, 2018, 11:08:29 PM »

check if you have default route

check if traceroute / mtr go up to a public dns
(8.8.8.8 - google one )

if yes
try to go in admin interface
https://internal-ip-of-server/server-manager

to domains >modify corporate DNS settings

set some public DNS servers
( EX
8.8.8.8
4.2.2.1   
)

and check again
if everybody's life around you is better, probably yours will be better
just try to improve their life

Offline Jean-Philippe Pialasse

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Re: dns suddenly stopped resolving names - now no email [solved]
« Reply #2 on: June 12, 2018, 01:29:39 PM »
As stated by the original poster when he marked the thread as solved:

Quote
The problem was caused by a bad backup script, which filled the disk up.