Hoary / kernel 2.6.9: Gaim cannot connect to AIM/ICQ?

[Klaus Alexander Seistrup]

On Tue, 21 Dec 2004 16:20:40 +0100, Le grand pinguin <rm at mh-freiburg.de> > 

>> If MTU was the problem, wouldn't it affect all sites, and not just
>> AIM/ICQ/Netscape (and a few others)?
> 
> It might be a bit more complicated: if your router does connect to your
> ADSL modem with PPP over ethernet the MTU on that segment will be
> smaller than the 1500 for ethernet (max ethernet frame size - ppp frame
> header size which usually comes dowm to 1492).

The router has a builtin ADSL modem.  It's a Cisco 678.

> This is all rather invisible to the end user as long as path mtu discovery
> works ... Now, some (stupid?) Websites dissable ICMP traffic at all and
> path mtu discovery (which does use ICMP) breaks. You might end up with
> a server sending you 1500 size packages with the don't-fragment bit set
> that never reach you because the package is to big to get through your
> PPPoE segment but can't be fragmented ....

I think I understand your reasoning, but why would it be a problem all
of a sudden?  I have used this setup for years.  Why would it break
with 2.6.9?

But now you're at it:  I actually put

  net/ipv4/ip_always_defrag=1

in my sysctl.conf, but now that I wanted to disable it, I discover
that the pseudo file no longer exists.  How do I control defrag'ing in
2.6.9?  And which value should I use?

> What happens if you manually set your MTU to 1492? A simple 'ifconfig
> eth0 mtu 1492' should be enough.

I used "ip link set eth0 mtu 1480", and it had no effect on the
previous mentioned hosts -- I still cannot connect to
login.oscar.aol.com, login.icq.com or www.netscape.net...

Cheers,

-- 
Klaus Alexander Seistrup
SubZeroNet · Copenhagen · Denmark