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SSH connection freezes

Hi,

we curently experience some odd problem.

Connecting to an external server via ssh works.
Loging in with user and password works.
Sending some "small" commands works.
But if I send a command that comes with a larger answer my console freezes.
For example I try to open a text-file via VI.

With tools like wireshark I can see while typing any letters into the console there are still packets sent and recieved.

If I establish a ssh connection from some other internet-connection without any fw in between it works without any problem.

I tried to disable IPS without success.
Packetfilter doesn't drop anything regarding this problem.
What else mitght be the problem?

We're running an ASG320 with v8.301

thanks
jauer

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0 jauer over 13 years ago

Related to this: OpenSSH FAQ
I tried to send additional keep alive packets though the connection was never inactive.

It really have to be related to the reveiving packet size, I think?

I also tested two systems located in other other networks: One located in our DMZ actually has a stable connection to this specific server. SSH does not freeze there.

What I did not mention in my first post: This only happens with this specific server all other servers we're connecting via ssh work very well.

Any suggestions?
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0 BarryG over 13 years ago

Is your MTU set correctly on the firewall for your External interface?

Barry
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0 jauer over 13 years ago in reply to BarryG

Thanks for your hint.

I also checked the MTU and tried to set different values but it is everytime the same behaviour.
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0 jauer over 13 years ago in reply to jauer

Now I lowered the clients MTU value down to 1400. Now it works. [:)]
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0 BarryG over 13 years ago

Assuming the client is inside the Astaro firewall, there should be some MTU setting that works on the firewall's external interface.

Barry
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