Fwd: How secure is my system?

["Greg Taylor" <greg.taylor () wardhadaway com>]

Hi,

I sent this to the list straight after joining but then did not receive any mail for about three  days so I wonder if I 
missed any replies.  Apologies for time wasted if this is so.

I have just rejoined the list after a job move.  Having left behind a "proper" firewall (and by that I mean a single 
server providing all proxying, authentication etc) I have taken on something I know a lot less about.  I am trying to 
perform a proper security appraisal of the system centered around potential threats to our system and whether those 
threats are matched by an appropriate level of security.  I could do with help on the latter.

Working from the inside we use Novell Border Manager which itself connects via a Cisco IOS router which does NAT.  At 
the moment we only connect via ISDN with all calls originating internally so I am prefectly happy.  We now need to 
intorduce a permanent connection (e-commerce!) .

Any constructive comments are VERY welcomed and valued but particular questions are:

How secure is IOS doing NAT?  If the Cisco is hacked thus giving the hacker our true IP addresses how secure is Border 
Manager?

Please respond offline if you prefer.

Greg

Greg Taylor - IT Manager - Greg.Taylor () wardhadaway com