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#1 2018-09-04 06:12:51

deathholes
Member
Registered: 2015-07-30
Posts: 21

ssh connection error

Hi,
I'm trying to ssh into my server via ssh. But the server gets disconnected frequently with the error "packet_write_wait: Connection to xx.xx.xx.xx port 22: Broken pipe".
It doesn't always happen when the server is idle. Sometimes it happens while I'm still on "nano". I've tried the "ServerAliveInterval" and "ClientAliveInterval" options in both client and server ssh config files.
Contrarily, this problem doesn't happen to all the other users.
I'm using arch linux and the server has ubuntu server 16.04.5 installed.
let me know if you need any log files etc.

thanks in advance

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#2 2018-09-04 07:33:46

seth
Member
Registered: 2012-09-03
Posts: 51,143

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#3 2018-09-04 09:07:02

deathholes
Member
Registered: 2015-07-30
Posts: 21

Re: ssh connection error

Adding "IPQoS throughput" to /etc/ssh/ssh_config doesn't work.

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#4 2018-09-04 15:02:10

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 19,785

Re: ssh connection error

Are you on the same LAN?  On the same Subnet? Are you going across the Public Internet? Are you using wireless?
The point being:  Is it a reliable connection? Broken Pipes happen to me when I am communicating with my server at home and my ISP has one its bi-hourly hiccups.

A work around is to use tmux or termina so that, at the least, you can reestablish a session and pick up where you left off without loosing your work.


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

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#5 2018-09-05 04:04:32

deathholes
Member
Registered: 2015-07-30
Posts: 21

Re: ssh connection error

I use tmux already. It's on the same LAN. Not in the same subnet. Not using the public internet and not on wireless.
The machine is a lab shared machine.
I wanted to use sshfs which seems impossible with this kind of unreliability.

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#6 2018-09-07 06:36:28

deathholes
Member
Registered: 2015-07-30
Posts: 21

Re: ssh connection error

Moving to the same subnet works but i'm not sure why.
anybody got any idea?

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#7 2018-09-07 06:58:41

fukawi2
Ex-Administratorino
From: .vic.au
Registered: 2007-09-28
Posts: 6,224
Website

Re: ssh connection error

What is routing between the subnets? Sounds like an over-zealous firewall and faulty state-tracking on a middle device.

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#8 2018-09-07 14:13:04

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 19,785

Re: ssh connection error

Just a hunch, try (as root) sysctl net.ipv4.tcp_ecn=0


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

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#9 2018-09-15 03:43:50

deathholes
Member
Registered: 2015-07-30
Posts: 21

Re: ssh connection error

fukawi2 wrote:

What is routing between the subnets? Sounds like an over-zealous firewall and faulty state-tracking on a middle device.

It's an institute-wide network so no idea about the level of strictness of the firewall. It does block gaming and *not safe for work* sites.

ewaller wrote:

Just a hunch, try (as root) sysctl net.ipv4.tcp_ecn=0

Right now out of station. will check and tell. By the way what does this command do?

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#10 2018-09-15 07:56:42

seth
Member
Registered: 2012-09-03
Posts: 51,143

Re: ssh connection error

If it's not congestion, see https://wiki.archlinux.org/index.php/Se … nd_tunnels to mitigate your pain until the local admin has fixed subnet routing.

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#11 2018-09-15 14:32:09

ewaller
Administrator
From: Pasadena, CA
Registered: 2009-07-13
Posts: 19,785

Re: ssh connection error

deathholes wrote:

By the way what does this command do?

It is a new issue and is a bit obscure.  https://wiki.archlinux.org/index.php/Ne … tification
It is a work around for some broken routers that do not respond well to a recent change in the kernel.systemd

Last edited by ewaller (2018-09-15 14:33:21)


Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

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