From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ed Wildgoose <lists@wildgooses.com>
Date: Mon, 10 Jan 2005 22:16:02 +0000
Subject: Re: [LARTC] wondershaper with ssh on a non-standard port
Message-Id: <41E2FEA2.2090208@wildgooses.com>
List-Id: <lartc.vger.kernel.org>
References: <20050110194905.GM13970@queeg>
In-Reply-To: <20050110194905.GM13970@queeg>
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To: lartc@vger.kernel.org

Hi,

>having read the docs and the wondershaper script itself, it occurred to 
>me that the documentation promises an immediate drop in interactive app 
>latency, specifically mentioning SSH as a big winner. 
>however, looking through the script i can't really tell just *how* 
>wondershaper figures out which port my SSH daemon is running on. 
>
>so what i'd like to know is, if i'm running my sshd on, say, port 222, 
>do i need to make any changes to the wondershaper script, or will it 
>figure out the right number automagically (e.g. from /etc/services, 
>where SSH is already correctly assigned to port 222) ?
>(conversely, does it 'need' to figure out this port number at all?)
>  
>

It's been a while since I looked through wondershaper, but the relevant 
lines are apparently these:

    # TOS Minimum Delay (ssh, NOT scp) in 1:10:

    tc filter add dev $DEV parent 1:0 protocol ip prio 10 u32 \
          match ip tos 0x10 0xff  flowid 1:10

So it seems to be matching based on the "type of service" bits in the IP 
packet.  I seem to remember that SSH actually sets the IP tos bits 
correctly?

So it *should* work when ssh is on another port.  I guess you need to 
either tweak the script (if you want a quick fix then just mark anything 
to/from port 222 as high priority), or else figure out why your packets 
aren't matching the required rule....

Good luck

Ed W
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