Re: NAT external/Public IP

[Ansgar -59cobalt- Wiechers <bugtraq () planetcobalt net>]

On 2007-10-30 Grant Donald wrote:
> With PAT private IP addresses are hidden from the outside world. This
> basically makes the job of hacking into a system more difficult,
> because the original host's IP address and source port is unknown. 

This is mere obscurity. It doesn't make a host any more or less secure
than it already is. Like I said before: either a host is secure, then it
doesn't matter if an attacker knows the address, or it isn't secure,
then you're "security" is based on the hope that an attacker won't
discover the host.

> Depending on firewall capabilities (or lack of capabilities) ports may
> need to be opened inbound for certain applications to work (e.g..
> ident & pptp). A horizontal scan of such a network could produce a
> wealth of knowledge, if that network does not support port address
> translation.

Ummm... wot? Why would you want to allow any inbound connections into
your LAN? And how would an attacker be able to scan your network from
the outside? For some obscure reason you seem to assume that using
public IP addresses in your LAN means that the firewall at the perimeter
magically allows access from WAN to LAN. This assumption is wrong.

Regards
Ansgar Wiechers
-- 
"All vulnerabilities deserve a public fear period prior to patches
becoming available."
--Jason Coombs on Bugtraq