FTP connects and immediately closes

[Matt Hearn]

Hey all! I'm having a funny problem with FTP on an 11.11 server. If I FTP to it from another server, I get a normal connection, prompts for password, lets me in, all that good stuff. However, if my customer tries to come in from his side, he gets:

c:\>ftp server.domain.com
Connected to server.domain.com
Connection closed by remote host.

I'd say it was just a firewall issue, but it looks like the connection happens and then is immediately dropped! Why would it happen to them, and not me? They can traceroute to the server without any problems, although they are half-way around the world from it so the trace takes longer.

[Matt Hearn]

Additional info: they can traceroute to my server, but I can't traceroute back to them, although I can ping them.

[Steven E. Protter]

Shalom,

On the server:
inetd -l

enahanced logging

tail -f /var/adm/syslog/syslog.log

Try to connect.

See the configuration of ined.conf, there may be a problem.

SEP

[Jonathan Fife]

Anything in the syslog? Do you have a hosts.allow file that needs to be updated to include their address?

[Peter Godron]

Also please dont' forget that ftp uses two ports (20/21) for data/control.
If one of them is firewall blocked, you have a problem.

[Bill Hassell]

The one-way traceroute implies network restrictions. Check with your netadmins to see if they block outgoing ftp. As mentioned, ftp requires two ports, one for control and the other for data, so perhaps the data port is blocked. Most firewalls have a macro rule for ftp that handles both together but perhaps this firewall is limiting one of the ports.

[Mancboy]

are you using /etc/fptd/ftpaccess?
This can deny address ranges, force ftp to listen on certain network cards. It can also force reverse look ups so if the reverse look up fails, it bombs you out.

[Roland Piette]

Hi Matt,

He can 'traceroute' you but you cannot do it.

Control the routing table on your site. Routing rules can be different !

Roland

[Rita C Workman]

Have you tried to FTP from the 'outside' like your client ?
Could their be a variance in the ftp protocol being used ? .. like if your shop only allows sftp or ftps to connect externally, but he's trying to ftp only.

Just something to check,
Rgrds,
Rita