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Rungano
Asked: 2009-08-05 01:38:19 +0800 CST

FTP connection hanging on 200 Welcome to blabla FTP services

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I am having problems when connecting to a remote ftp server that is running on UNIX.When I try to coonect it freezes on the welcome screen and it dos=esnt prompt for password and username. Connected to 17.17.0.181.
220 Welcome to the Blabla FTP service

It just freezes there nothing, if I try to kill it with control c or z it wont die! I have to log on to another console and do the kill PID thingy. I know I am certain its something to do with firewall or routing because I can connect from else where.

My firewall iptables has the following settings
modprobe ip_nat_ftp ports21
modprobe ip_conntrack_ftp
iptables -A FORWARD -m state --state ESTABLISHED -j ACCEPT
iptables -A FORWARD -p tcp -m tcp -m state --dport 21 --state NEW -j ACCEPT
iptables -A FORWARD -p tcp -m tcp -m state --sport 20 --state RELATED -j ACCEPT
iptables -A FORWARD -p tcp -m tcp -m state --dport 1024:65535 --sport 1024:65535 --state RELATED -j ACCEPT
Anybody out there your help is much appreciated.

linux ftp troubleshooting iptables

1 Answers

  1. Is the firewall running on the same machine as the ftp daemon? If so, I think you need to use the INPUT chain, not the FORWARD chain. The FORWARD chain is used in packet forwarding. When the packets should be processed locally, they will go through the INPUT chain, not the FORWARD chain.

    This "drawing" (from the netfilter website) explains which chains do what.

    Incoming                 /     \         Outgoing
       -->[Routing ]--->|FORWARD|------->
          [Decision]     \_____/        ^
               |                        |
               v                       ____
              ___                     /    \
             /   \                  |OUTPUT|
            |INPUT|                  \____/
             \___/                      ^
               |                        |
                ----> Local Process ----
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