Re: IP MASQUERADING broken again from v1.3.81 onwards

Herbert Rosmanith (
Fri, 5 Apr 1996 18:10:53 +0200 (MET DST)

> > I remember reading a piece of source code, was it ftp or ftpd, where
> > port 20 was commented out, and a 0 was inserted instead, so the system
> > will create its own port.
> Maybe, but most (all?) ftp daemons still seem to use port 20 and
> firewall literature usually lists just this particular port.

no, not all do so.
in particular wu-ftpd does not use port 20 ! (check the source)
you can verify this yourself by doing some ftp, and type
netstat -na | grep <target-ftp-host>

so, some ftpd do use ftp-data=20, some do not, and at least wu-ftpd is
one of those not using port 20. kinda annoying for statically
configured firewalls ...