Bug 29999 – dhclient overwrites resolv.conf

Bug 29999 - dhclient overwrites resolv.conf


Summary:	dhclient overwrites resolv.conf

Status:	CLOSED FIXED

Product:	UCS
Classification:	Unclassified
Component:	Network
Version:	UCS 3.1
Hardware:	Other Linux

Importance:	P5 normal (vote)
Target Milestone:	UCS 3.1-0-errata
Assigned To:	Stefan Gohmann
QA Contact:	Janek Walkenhorst

URL:
Keywords:

Depends on:
Blocks:	29885
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Reported:	2013-01-10 21:28 CET by Stefan Gohmann
Modified:	2013-01-15 15:19 CET (History)
CC List:	1 user (show)

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Description Stefan Gohmann

2013-01-10 21:28:16 CET

dhclient overwrites the resolv.conf with the DNS server given via DHCP. When ifup/ifdown will be used to configure the interface everything works fine, because /etc/network/if-up.d/00_resolvconf writes the given DNS server to dns/forwarder and so on.

If the lease expires, dhclient will be executed and the resolv.conf contains only the given DNS server.

Workaround:

cat >>/etc/dhcp/dhclient-enter-hooks.d/resolvconf <<__HERE__
#!/bin/bash
ucr commit /etc/resolv.conf
__HERE__

The real fix should check that the nameserver given via DHCP will be set as dns/forwarder at least on a DC.

Comment 1 Stefan Gohmann

2013-01-15 09:04:37 CET

A new dhclient-exit-hooks.d has been added:
 /etc/dhcp/dhclient-exit-hooks.d/resolvconf

It checks similar to /etc/network/if-up.d/00_resolvconf the /etc/resolv.conf. If a nameserver was given via DHCP this nameserver is added to the dns/forwarder* list. And the resolv.conf is re-created with the nameserver from UCR.

Comment 2 Janek Walkenhorst

2013-01-15 13:57:19 CET

Tests:
 Fehler wird durch Installation des Paketes behoben, beim renew wird die Datei wieder korrigiert und die Nameserver als forwarder eingetragen.

Advisory: OK

Comment 3 Moritz Muehlenhoff

2013-01-15 15:19:09 CET

http://errata.univention.de/3.1-errata17.html