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Old 07-01-2005, 05:43 PM   #1
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Registered: Jul 2005
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adsl connection drops when port forwarding large files


I have a home network involving a firewall and then a number of machines sitting behind this firewall. All redhat 9. I have an odd problem in that my adsl connection drops sporadically. This only happens when copying large files via scp2 from the remote machine to a machine behind the firewall. It doesn't happen however if i just copy directly onto the firewall.

It must therefore be something about the forwarding. It will do small files but large ones cause the connection to drop.

I use port 2222 to copy to the machine behind the firewall and 22 to go directly to the firewall.

I use narc as a firewall and have the forwarding

iptables -t nat -A PREROUTING -i ppp0 -p tcp -d --dport 2222 -j DNA
T --to
iptables -A FORWARD -i ppp0 -o eth1 -p tcp -d --dport 22 -j ACCEPT

Any help appreciated,

Old 07-03-2005, 09:05 AM   #2
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Registered: Feb 2002
Location: Szczecin, Poland
Distribution: Gentoo, Debian
Posts: 2,458

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Do you have an ESTABLISHED/RELATED rule in FORWARD before the ACCEPT rule?
do iptables-save to list active rules

Last edited by peter_robb; 07-03-2005 at 09:06 AM.


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