Re: Infrastructure Filtering (was Re: Patching for Cisco vulnerability)

[Niels Bakker <niels=nanog () bakker net>]

Hi Charles,

* spork () inch com (Charles Sprickman) [Fri 18 Jul 2003, 22:21 CEST]:
> If I recall correctly, Rob's Secure IOS Template touches on filtering
> known services (the BGP listener, snmp), but what are people's feelings
> on maintaining filters on all interfaces *after* loading a fixed IOS?

You'll have to weigh the benefits to the downsides.

Benefits to filtering IP packets with those four protocols:
- You're protecting your network, and possibly others, from failure
- You can see pretty quickly when someone's trying to attack you or
  other networks

Downsides:
- You're hampering the use of several technologies
- Possible impact on the load / forwarding capacity of your router
  (dependent on its architecture)

Personally I'd try to filter packets destined for known router
interfaces and let the rest pass through.  And of course not run
known-buggy software (famous last words...).


        -- Niels.

-- 
   <anselm> rather than calling it bluetooth the protocol should be called
            'erikson wireless cellphone earpiece protocol' since that seems
            to be its only real use.