-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 It looks like my rather eloquent reply to Thomas' observations didn't make it to the list, so I'll be plain, since I didn't save what I wrote, and don't feel like rewriting all of it again. In a nutshell, I've now got: iptables -t nat -A OUTPUT -p tcp -o eth0 --dport 25 -j DNAT - --to-destination aaa.bbb.ccc.ddd When I run this, I simply get: iptables: Invalid argument which is one of the most uninformative error messages I've seen. BTW, in case anyone is wondering, aaa.bbb.ccc.ddd is being replaced with a valid IP address in my script, so that's not the problem. If anyone has any other suggestions, I would be glad to hear them. Also, thanks to those who helped so far. Greg - -- Free domains: http://www.eu.org/ or mail dns-manager at EU.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQFA53vh7s9z/XlyUyARAoolAJ498Swybk9V21IOc7HYn2AhJ4Hr0wCfbL2P GTE/RBN2FILf2RA223of5s4= =bYyZ -----END PGP SIGNATURE-----