Firewall Wizards mailing list archives
Re: Firewall comparison in Data Communications
From: "Ge' Weijers" <ge () progressive-systems com>
Date: Thu, 3 Jun 1999 11:39:21 -0400
On Thu, Jun 03, 1999 at 07:44:58AM -0400, Steven M. Bellovin wrote:
Right. More fundamentally, firewalls can't protect you against bugs at a higher level of the protocol stack. An IP+port number firewall (i.e., a typical packet filter) is blind to TCP holes. For that matter, it's blind to attacks based on other portions of the IP packet that it doesn't look at -- 'ping of death' comes to mind.
Even dynamic packet filters (marketing-speak: Multi-Layer Stateful Inspection firewalls) only have limited value here. Most of them don't match 'host/network unreachable' ICMP messages to actual connection attempts. Not that this _can't_ be done correctly, the overhead is just considered too high. And there's your hole to get a variant of ping of death through. Ge' -- - Ge' Weijers Voice: (614)326 4600 Progressive Systems, Inc. FAX: (614)326 4601 2000 West Henderson Rd. Suite 400, Columbus OH 43220
Current thread:
- Re: Firewall comparison in Data Communications, (continued)
- Re: Firewall comparison in Data Communications Chris Brenton (Jun 03)
- Re: Firewall comparison in Data Communications Ge' Weijers (Jun 02)
- RE: Firewall comparison in Data Communications David Newman (Jun 02)
- RE: Firewall comparison in Data Communications Kevin Steves (Jun 14)
- RE: Firewall comparison in Data Communications W J La Cholter (Jun 03)
- Re: Firewall comparison in Data Communications Don Kendrick (Jun 03)
- RE: Firewall comparison in Data Communications Russ (Jun 03)
- RE: Firewall comparison in Data Communications csingletary (Jun 03)
- RE: Firewall comparison in Data Communications Rob Polansky (Jun 04)
- Re: Firewall comparison in Data Communications Steven M. Bellovin (Jun 03)
- Re: Firewall comparison in Data Communications Ge' Weijers (Jun 03)
- Re: Firewall comparison in Data Communications dnewman (Jun 03)
- Re: Firewall comparison in Data Communications Ge' Weijers (Jun 03)
- Re: Firewall comparison in Data Communications Kevin Steves (Jun 14)
- RE: Firewall comparison in Data Communications Robert Graham (Jun 03)