Delays in ssh connections between two local Linux computers

[Kfir Lavi]

On Mon, Sep 12, 2011 at 4:37 PM, Shlomi Fish <shlomif at gmail.com> wrote:

> Hi all,
>
> (I apologise from writing from my gmail.com account, but as you'll see
> below,
> writing from my home E-mail account is not bearable.).
>
> I have a desktop x86-64 Core i3 machine (running Mageia Linux 1) that
> connects
> via wired Ethernet to my NAT/router and there is a remote x86-64 Core Duo
> laptop (running Mageia Linux 2), connected via wireless. Often when I type
> commands on bash on the remote laptop via ssh, there is a significant
> delay,
> and moreover running claws-mail or gringotts (two fast gtk+ apps) from the
> laptop are slow, which hadn't been the case with my older desktop machine.
> tcpdump -i wlan0 on the laptop and htop on the laptop show nothing that
> might
> cause it.
>
> The delays in the connectivity were not bad with the previous desktop
> machine
> which was an old Pentium 4 2.4GHz machine, which was much slower and
> underpowered.
>
> So far I tried:
>
> 1. Doing /etc/init.d/iptables stop on the desktop machine.
>
> 2. Relocating the laptop closer to the wifi NAT/router.
>
> Neither of those helped.
>
> Can anyone shed any light on this?
>
> Regards,
>
> -- Shlomi Fish
>
>
> --
> ------------------------------------------
> Shlomi Fish http://www.shlomifish.org/
>
> Electrical Engineering studies. In the Technion. Been there. Done
> that. Forgot a lot. Remember too much.
>
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> Linux-il at cs.huji.ac.il
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>

Hi Shlomi,
You need to edit 2 files:
1. edit /etc/ssh/sshd_config and add the line 'UseDNS no'
2. edit /etc/nsswitch.conf and make sure the line:
 'hosts:          files dns'
have just the 'files' and 'dns'. delete everything else from this line.

This will make ssh instant!

Kfir
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