Comment 234 for bug 417757

Revision history for this message
Yermo (yml-yml) wrote : Re: [karmic regression] all network apps / browsers suffer from multi-second delays by default due to IPv6 DNS lookups

@Laurent yes. /ALL/ network access regardless of application is affected. Please re-read the report I wrote. Yes, this has nothing to do with the IPv6 DNS lookup problem. IPV6 AAAA record lookup was one issue that would cause the slow connections so many people are experiencing. My point is that while the IPv6 lookup issue has been resolved, it is not the only cause of the slow dns lookup/connection symptoms people are experiencing.

As I have said, IPV6 is /disabled/ on my machine via grub. IPV6 is disabled in firefox. IPV6 IS NOT THE SOLE REASON FOR SLOW DNS AND NETWORK CONNECTION IN UBUNTU. i have verified this here. Maybe it should be listed as a separate bug, but none of the other bugs I have found (of which there are many) seem to match the symptoms I'm seeing here exactly.

Slow dns lookups. DNS lookup failure 30% of the time or so. Connection failure 30% of the time or so. Extremely slow net connectivity over a wired connections. I've tried every combination of work around I could find on the net to no avail.

Then I upgraded the firmware on my DI-707 router and suddenly the problem disappears. The confusing thing is that Ubuntu 8.04, WinXp and EVERY SINGLE DISTRIBUTION BEFORE had no issue with this router. It seems to be restricted to recent 2.6 kernels.

I had read somewhere, I'm sorry I have forgotten where, that there was some TCP/IP standards issue that someone had decided to implement too strictly in recent kernels which caused connections through many legacy routers/switches/firewalls to fail (which is why I tried the firmware upgrade).

At this point, for me, the problem seems to be solved, but I have the feeling that there are many Ubuntu users out there that are still suffering from slow/failing dns lookups and the IPV6 issue does not explain all of them.

There is still some network level problem.

But like I said, the firmware upgrade on my DI-707 seems to have worked around whatever problem Ubuntu has.

I'm reporting this in an attempt to be helpful; too often in my own software business customers who are running into trouble with our software simply don't report their experiences so we have no idea that there's a problem.