Re: FTP Server Question

From: those who know me have no need of my name (not-a-real-address@usa.net)
Date: 02/10/03 

From: those who know me have no need of my name <not-a-real-address@usa.net>
Date: 10 Feb 2003 18:11:21 GMT

in comp.security.firewalls i read:

>I'm trying out the new Bullet Proof ftp server that allows passive
>connections and resolves external ip from within a firewall. I don't
>understand why the server doesn't work when I disable UDP on the ports that
>I have forwarded through my firewall. I did have hostname lookup
>enabled........is that what is requiring UDP? I've seen information saying
>that you need both tcp and udp enabled and I've seen information that FTP
>only uses TCP.

hostname lookup requires dns service, which requires udp and tcp to
destination port 53 from whichever local port(s) your resolver uses,
typically either 53 or one or more ephemerals. ftp uses tcp destination
port 21 toward the server from any unreserved source port (i.e., >1023),
and an arbitrary ephemeral port towards the client for each data connection. 

-- 
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