"Creating resolv.conf" every minutes

wxop · Dec 17, 2010, 9:51 AM

I'm using a WAN, LAN, and WLAN ports, Captive Portal on the WLAN and DHCP servers on the LAN and WLAN.

Here is what i get in /var/log/system.log:


Dec 17 10:31:18 gate dhclient: Creating resolv.conf
Dec 17 10:32:18 gate dhclient: RENEW
Dec 17 10:32:18 gate dhclient: Creating resolv.conf
Dec 17 10:33:18 gate dhclient: RENEW
Dec 17 10:33:18 gate dhclient: Creating resolv.conf
Dec 17 10:34:18 gate dhclient: RENEW
Dec 17 10:34:18 gate dhclient: Creating resolv.conf
Dec 17 10:35:18 gate dhclient: RENEW
Dec 17 10:35:18 gate dhclient: Creating resolv.conf
Dec 17 10:36:18 gate dhclient: RENEW
Dec 17 10:36:18 gate dhclient: Creating resolv.conf
Dec 17 10:37:18 gate dhclient: RENEW
Dec 17 10:37:18 gate dhclient: Creating resolv.conf
Dec 17 10:38:18 gate dhclient: RENEW
Dec 17 10:38:18 gate dhclient: Creating resolv.conf
Dec 17 10:39:18 gate dhclient: RENEW
Dec 17 10:39:18 gate dhclient: Creating resolv.conf

I've observed this behaviour on all screenshots i've upgraded to during the last two Months.
Current version: 2.0-BETA4 Built On: Thu Dec 16 14:34:04 EST 2010

More Infos:


# ls -l /etc/resolv.conf
lrwxr-xr-x  1 root  wheel  20 Dec 15 08:28 /etc/resolv.conf -> /var/etc/resolv.conf
#ls -l /var/etc/resolv.conf
-rw-r--r--  1 root  wheel  56 Dec 17 10:27 /var/etc/resolv.conf
#more var/etc/resolv.conf
 domain lo.lo
 nameserver 10.1.10.1
 nameserver 10.1.10.11

Is this normal? If not, Where should I investigate?

jimp · Dec 17, 2010, 5:37 PM

Looks like your upstream DHCP provider has a one-minute lease timeout. Your DHCP client is renewing every minute, and when it does, it rewrites the DNS servers based on the DHCP reply.

Such a ridiculously short lease time is bound to cause other issues… If your ISP is open to fixing that, it has to be fixed on their side.

wxop · Dec 18, 2010, 1:20 PM

Jimp, Thank you for the reply

Yes my ISP DHCP server may renew its Lease every minutes. I could bypass this by assignign the static IP given by my ISP instead of using DHCP on WAN: In my current configuration, it would not be the most convenient.

But Is it normal that pfSense rewrite the resolv.conf file every time, despite I tell him NOT to use my ISP DNS servers.
(Systeme/General Setup/"Allow DNS server list to be overridden by DHCP/PPP on WAN" is NOT ticked)?

Theses line in resolv.conf:
domain lo.lo
nameserver 10.1.10.1
nameserver 10.1.10.11

are my own internal DNS servers…Absolutely not related to the ISP.

jimp · Dec 18, 2010, 4:07 PM

Not sure what the logic for updating DHCP received DNS servers looks like (I haven't looked at the code for that in 2.0 in quite a while), but if you have the allow override boxed unchecked it should probably not be updating that file.