Hacking Linux Exposed

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To: Firewall Wizards List firewall-wizards@honor.iscalabs.com
From: Administrator <admin@big_company.com>
Subject: Problem communicating with ftp server

We have an ftp server behind a Linux firewall running
ipchains. It's your standard 3 interface firewall,
(internet/dmz/lan) as shown here:

      Internet -------------  firewall -------- lan
      (209.158.562.0/26)          |         10.0.0.0/24
                                  |
                                  | dmz (10.1.0.0/24)
                                  |
                               ftp server

There's no problem with establishing the initial
ftp connection, however as soon as it tries to
send data (an ls, put/get, etc) it simply hangs.
We've tried everything we can, and we can't figure
out what's going wrong.

Any help gladly appreciated. Thanks.

---------------------------------------------------------
Johnathon Myers                          312.555.8862
Security Department Head                 Big Company, Inc

"Zathras understand. No, Zathras not understand, but Zathras do."
"Very sad life. Probably have very sad death. But at least there is symmetry."
"Babylon 5 was our last, best hope, for peace."

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