Re: 44BSD port of land.c

[mycroft () MIT EDU (Charles M. Hannum)]

Peter <deviant () UNIXNET ORG> writes:

> This seems to work, as long as you've got NetCat:
>
> -----
> #!/bin/bash
> nc -s $1 -p $2 $1 $2
> -----
>
> where $1 is the host, and $2 is the port (139,23, 25, whatever)

This is actually a separate bug.  It used to be that in the 4.4BSD
stack (and probably earlier versions) a TCP socket connecting to
itself would cause a SYN war, via a different code path than the
`land' sttack.  We fixed this a few years ago in NetBSD, and our fix
for the `land' attack (which I'll post about in a moment) still allows
a socket to connect to itself -- although truthfully I'm not sure how
useful this behaviour really is.