mail problem - iptables

[Matthew G. Marsh]

On Thu, 11 Oct 2001, infomail@nobarrier.co.za wrote:

> Hi all
>
> Has any one had a problem like this
>
> sendmail mail is running on the firewall, the mail server is sending and
> receiving mail fine. But the are one or to mail server out there that I
> can connect to they can telnet to the firewall on oport 25 but when I
> telnet them on port 25 it just sits there and does not come back with a responces.
> I have done a tcpdump from the firewall machine that has
> ipchains(working) but on a different network and iptables ( not working)

Had this problem when using tcp_ecn to Exchange boxen. Still have this
problem. Turning off tcp_ecn will then allow the connection to occur.

> I have also done it from a iptables machine to the same mail server on
> another network and it does the sames
>
> I now one of the firewall on the other side is a pix firewall, does it
> maybe handel syn and ack differently

> PLEASE REPLY TO jonathan@nobarrier.co.za
>
> Thank you
> Jonathan

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Matthew G. Marsh,  President
Paktronix Systems LLC
1506 North 59th Street
Omaha  NE  68104
Phone: (402) 932-7250 x101
Email: mgm@paktronix.com
WWW:  http://www.paktronix.com
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