solved: Can't connect to some internet servers

[ntzim]

Hi all,
I can't connect to the address www.tee.gr, witch is my ISP. The problem came when I upgrade to kubuntu 7.04. I experience the same problem with windows vista. For vista there is a workaround by giving:

netsh interface tcp set global autotuninglevel=disabled

in their console.
I can't understand what this code means.

What can't I do in kubuntu to connect.

Thanks


Solution
The problem is exactly the same as in vista, and is caused because some firewalls can't handle "Dynamic Rightsizing" as is known in the linux world or "Receive Window Auto-Tuning" (vista world).

The workaround in linux is:

open /etc/sysctl.conf with your favorite editor and add the following line:

net.ipv4.tcp_rmem = 4096 87380 174760

the in a console give:

#sudo sysctl -p

that is all

Many thanks to UnicornRider and DMurray for their answers and mostly G. A. of tee.gr who gave the solution.

[penguin.ch]

Re: Can't connect to some internet servers

I can't understand what this code means.

Google (1st hit): http://computerbits.wordpress.com/20...a-auto-tuning/

[ntzim]

Re: Can't connect to some internet servers

Thanks for the reply.
The real question is how is this code translated in Linux because I have the same problem in my kubuntu box. From www.tee.gr they told me that it is because of some configuration they made to their firewall / router but they weren't really helpfull.
It is not a problem of konqueror. I can't connect to their mail server either.

In my old kubuntu 6.06 I can connect normally and get mail to.

Thanks

[penguin.ch]

Re: Can't connect to some internet servers

The real question is how is this code translated in Linux

Not at all, I dare say.

I have the same problem in my kubuntu box

The real problem is your (so-called) ISP :P

they told me that it is because of some configuration they made to their firewall

See what I mean? They've messed things up and leave the cleaning-up to you ...

It is not a problem of konqueror. I can't connect to their mail server either.
In my old kubuntu 6.06 I can connect normally and get mail to.

Interesting - but way too vague ... (and I can't even read their web pages ...).

--

The only way to proceed coming to my mind (sorry ...):

You may try to "compare & contrast" the network settings (eth0/1, ipv4/6, etc.) of "06.06" vs. "07.04"

[ntzim]

Re: Can't connect to some internet servers

They've messed things up and leave the cleaning-up to you ...

Maybe, or they don't support "Receive Window Auto-Tuning". If this is the case, kubuntu also made a step back in this one.

I didn't get anything in my first try to compare the network settings.

I am going to use plan B also ie. ask for their firewall messages containing my IP, to see what is going on.

[DMurray]

Re: Can't connect to some internet servers

Maybe, or they don't support "Receive Window Auto-Tuning". If this is the case, kubuntu also made a step back in this one.

Not quite. Newer versions mean, in general, more secure, updated packages, safer TCP stack, better personal firewalls. I definitely agree with UnicornRider in the "your ISP messed things up and left cleaning-up for you". They didn't even tell you what they did, so you could find a way to reconfigure your box to "give" what the new firewall "wants".
But it is unlikely to work, there is not much you can mess with TCP settings, so if your ISP blocks some kind of packets, and Linux just send them when requesting a connection, there's not much to do. Linux normaly works based on what standards say.
Feisty may have "tighter" security rules, though, but you need to know what they did, or you will end up having to install old software.

[ntzim]

Re: Can't connect to some internet servers

The ridiculous part of the hole story is that they use linux in their web and mail servers

I know that they have a few linux experts and I must contact with them.

Thank you guys. I will post a solution as soon as I find one.