dnsmasq works intermittently

Bug #1058089 reported by Andrej Prša on 2012-09-28
This bug affects 1 person
Affects Status Importance Assigned to Milestone
dnsmasq (Ubuntu)

Bug Description

When connecting to a home network, the wireless connection is established and does not drop, but package throughput works intermittently. When it is working, it works perfectly: the throughput is fast and reliable. It seems that traffic helps it. The issue is most notable on http requests. Flood pinging the router (or connecting to it) drops no packets during these breaks, but anything outside is unreachable. At the same time other computers experience no problems. These paucities in operation last from minutes to tens of minutes. Reconnecting to the wireless or rmmod/modprobing the module does not help.

The usual proposed remedies (passing 11n_disable=1 and/or swcrypto=1) make no obvious difference.

The most curious observations is that, during these intermittent breaks, /established/ traffic comes through. For example, an active gtalk session will remain active and fully responsive while all other traffic is interrupted.

The stock iwlwifi for 12.04 (3.2.0) does not work either. Using the most recent firmware. The wireless adapter worked perfectly with the 2.6 kernel, and it still works with Mint 11. Other devices have no issue with the AP.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-backports-modules-cw-3.4-3.2.0-30-generic 3.2.0-30.15
ProcVersionSignature: Ubuntu 3.2.0-31.50-generic 3.2.28
Uname: Linux 3.2.0-31-generic x86_64
ApportVersion: 2.0.1-0ubuntu13
Architecture: amd64
Date: Fri Sep 28 07:54:58 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
 PATH=(custom, no user)
SourcePackage: linux-backports-modules-3.2.0
UpgradeStatus: No upgrade log present (probably fresh install)

Andrej Prša (andrej-prsa) wrote :
Andrej Prša (andrej-prsa) wrote :
Andrej Prša (andrej-prsa) wrote :
Andrej Prša (andrej-prsa) wrote :

I finally managed to get the problem fixed. The issue is not with the iwlwifi modulce, it is with ubuntu's new dns resolver. I edited /etc/NetworkManager/NetworkManager.conf and commented out the dns=dnsmasq line. From then on, all problems have disappeared. I am refiling this bug as the dnsmasq bug.

affects: linux-backports-modules-3.2.0 (Ubuntu) → dnsmasq (Ubuntu)
Serge Hallyn (serge-hallyn) wrote :

Thanks, Andrej. Were there any helpful messages in /var/log/syslog?

Changed in dnsmasq (Ubuntu):
importance: Undecided → Critical
Serge Hallyn (serge-hallyn) wrote :

I believe I have a laptop (out of reach at the moment) with iwlwifi. if so i'll see if i can reproduce.

Thomas Hood (jdthood) on 2012-10-20
summary: - Intel 5100 AGN (iwlwifi) hangs frequently -- intermittent operation
+ dnsmasq works intermittently
Thomas Hood (jdthood) on 2012-11-04
Changed in dnsmasq (Ubuntu):
status: New → Incomplete
Thomas Hood (jdthood) wrote :

The symptoms are actually quite similar to the ones described by Wolf Rogner in bug #998712, so I am going to mark this report as a duplicate of that one.

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