inaccessible website via ubuntu 7 networking platform

[Daniel Skinner]

Ubuntu 7.04, tested on two different machines found on the same network; worth noting these are the only two machines running ubuntu.

Problem did not exist on Ubuntu 6.x

I hardly know how to explain this so ill state what has happened and what i have done.

There are two difficulties
1)
There is a website maintained by my company. It is a backend system accessible from the web via https://my.iscgrp.com/
2)
There is an ssh service running on a public machine i wont give out but needless to say the same problem.

The problem is this using, firefox2, opera9 or links; i can not connect to said public website. Or more specifically from what i can tell, it DOES connect but does not receive any data back.

As with the ssh connection I cannot connect.

I also have vmplayer installed on my machine. If I boot up my windows instance and use the virtual ethernet device (which is its own instance, own ip; thats to say, NOT bridged to the ubuntu ethernet device) I CAN connect to these things.

This problem persisted before i did the following as well. I had also noted that i could not connect to .local addresses on ubuntu 7.04 and found a bug report filed in regards to the /etc/nsswitch.conf file in regards to the following line
>> hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4

I'm uncertain which entry was the culprit but i do know its either mdns4_minimal or [NOTFOUND=return] and ill keep my wild guesses to myself.

Currently my /etc/nsswitch.conf looks as so to fix .local domain problems
>> hosts: files mdns4 dns #files mdns4_minimal [NOTFOUND=return] dns mdns4

Upon doing a tcpdump on my ubuntu end of the transaction with the webserver it appears to just hang around waiting for a response via mdns. If i push dns before mdns4 it hangs as well. If i install wins and add an entry preceeding those two, it hangs on wins as well waiting for a response.

upon doing a tcpdump in regards to the ssh connection from the server side and the ubuntu client side, both parties appear to be waiting on something from the other, though im not at all familiar with tcpdump to be making such deductions so i could be wrong.

As it is, im wondering if there is some sort of ssl package that is lessed from from 7 vs 6 or if a configuration file has changed somehow messing this up or if a compile went wrong for a low level service on ubuntu 7. Right now im looking to install 6 on a virtual machine on my workstation and investigate into config files.

Any help, ideas or feedback would be GREATLY appreciated.

[Daniel Skinner (dskinner)]

It is also worth mentioning perhaps, as a long shot to try and fix this problem, i tried disabling ipv6 as a last ditched effort last nite by doing the following

sudo nano /etc/modprobe.d/aliases
Find the line: alias net-pf-10 ipv6
Edit this to: alias net-pf-10 off
sudo modules-update
Save the file and reboot

and turned off ipv6 in firefox. This had no effect and i have since reenabled this functionalilty.

It is also worth noting that the other ubuntu machine is a complete unmodified base install (thats to say, no tinkering to fix this problem), only the one modified /etc/nsswitch.conf file

[didier (did447-deactivatedaccount)]

You have a broken router somewhere in the path.

A workaround:
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling