Re: Shorewall VOIP Traffic Control Configuration

Tom Eastep
Sun, 21 Jan 2007 02:50:09 -0000

Jim Duda wrote:
> Tom,
>
> Yes indeed, I figured that out last night.  I changed my configuration
> as follows (after reading more docs):
>
> tcrules:
> 1        $FW            0.0.0.0/0       udp     4569
> 1        $FW            0.0.0.0/0       tcp     4569
> 1        $FW            0.0.0.0/0       udp     5060
> 1        $FW            0.0.0.0/0       tcp     5060
> 2        0.0.0.0/0      0.0.0.0/0       icmp    echo-request
> 2        0.0.0.0/0      0.0.0.0/0       icmp    echo-reply
> 3        0.0.0.0/0      0.0.0.0/0       tcp     20

I suspect that the above rule isn''t doing what you expect.

FTP servers bind to *local* port 20 when they are creating an
active-mode connection back to the client. So the only time that there
is significant TCP traffic with destination port 20 is when an
active-mode client is *uploading* to an FTP server. So unless you have
active mode clients behind your firewall that do a significant amount of
uploading, the rule will only match ACK packets from active-mode clients
who are downloading.

-Tom
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