Box keeps talking to old DNS but config has changed

MikeDeltaBrown · 06-06-2014, 12:48 PM

Are these boxes using DHCP for their IP configs?

GaWdLy · 06-06-2014, 01:04 PM

Quote:

Originally Posted by MikeDeltaBrown

Are these boxes using DHCP for their IP configs?

^^ THis feeds into my comment about PEERDNS in the last post ^^

MarcLaf · 06-06-2014, 01:17 PM

Quote:

Originally Posted by MikeDeltaBrown

Since it happens at the same time you might want to check cron jobs: `crontab -l`

Checked it already. The only thing the jobs do are copy log files from one location to another.

MarcLaf · 06-06-2014, 01:21 PM

Quote:

Originally Posted by GaWdLy

What version of Red Hat?
What is in /etc/resolv.conf (IOW, are the contents changing, or static?)?
Also, are you performing a 'service network restart' or using stop/start? Has this persisted after a reboot?

You may need to add 'PEERDNS=no' to your ifcfg files for it to stop picking up on random DNS servers-depending on your version of RH.

RHEL 4 U2

resolv.conf contains the new name servers (previously had the old one).

I've been performing restart, not stop/start. Haven't rebooted the machine.

PEERDNS is set to yes. I looked at this part of the cfg a while ago.. didn't quite understand what it did but decided to leave it because we're not using DHCP on this box.

GaWdLy · 06-06-2014, 01:28 PM

Quote:

Originally Posted by MarcLaf

RHEL 4 U2

resolv.conf contains the new name servers (previously had the old one).

I've been performing restart, not stop/start. Haven't rebooted the machine.

PEERDNS is set to yes. I looked at this part of the cfg a while ago.. didn't quite understand what it did but decided to leave it because we're not using DHCP on this box.

PEERDNS=yes may be part of the issue. I believe it is a valid config option for non-DHCP applications, and it will change your DNS servers:

Code:

PEERDNS=<answer>
where <answer> is one of the following:

yes — Modify /etc/resolv.conf if the DNS directive is set. If using DHCP, then yes is the default.

no — Do not modify /etc/resolv.conf.

So remove the DNS1 or DNS2 entries for your IF, and set PEERDNS to 'no'. Then manually set your DNS servers in resolv.conf.

I'd suggest at the very least, a hard stop/start cycle on the service at the very least, but a reboot is likely preferable to that.

MarcLaf · 06-06-2014, 01:32 PM

Thanks GaWdLy. I'll try with =No tonight (err over the weekend) as I'd like to avoid a reboot if possible. If it's still doing it I'll talk to the guy and see if we can schedule one.

GaWdLy · 06-06-2014, 01:33 PM

Check this out, too: https://lists.fedoraproject.org/pipe...st/403171.html