replace "customer" with "public" Adi On Wed, Sep 19, 2001 at 04:16:59PM -0700, Dan Hollis wrote:

On Wed, 19 Sep 2001, Alex Yeung wrote:

...

Look at the following two URLs and then combine the config: http://www.cisco.com/warp/customer/63/nimda.shtml http://www.cisco.com/warp/customer/63/nbar_acl_codered.shtml

cco login required, thanks anyway

-- [-] Omae no subete no kichi wa ore no mono da. [-]

] > http://www.cisco.com/warp/customer/63/nimda.shtml ] > http://www.cisco.com/warp/customer/63/nbar_acl_codered.shtml ] ] cco login required, thanks anyway Try the non-CCO versions here: http://www.cisco.com/warp/public/63/nimda.shtml http://www.cisco.com/warp/public/63/nbar_acl_codered.shtml -- Rob Thomas http://www.cymru.com/~robt cmn_err(CE_PANIC, "Out of coffee...");

At 10:25 PM 9/19/01, Randy Benn wrote:

The basics of using NBAR as an IDS can be found here: http://iponeverything.net/CodeRed.html

The page above is specifically for Code Red, but the same technique can be used for blocking many different exploits. Just modify the class map as you like to block Nimda or anything else.

I'm presently running using the policy map config example, and having some real problems. While the traffic is no longer getting to the servers, the servers wind up with massive quantities of open TCP sessions. These take long enough to die that Apache winds up maxing out on processes. Two possible alternative approaches that I'd like to explore: 1. Some mechanism that builds on the present stuff, but sends a TCP RST off to the web server to get the TCP session terminated. 2. Alternative approach: use the timed access lists to place a temporary filter rule into the input filter for any IP address which matches on URL. This would protect the servers better, in that it'd block the TCP connections (after the first one) from a server entirely. This wasn't an issue really for CodeRed, but is a major issue for nimda, since it opens many connections. If anyone has insight on how to implement either of these, I'd like to hear about it. ----------------------------------------------------------------- Daniel Senie dts@senie.com Amaranth Networks Inc. http://www.amaranth.com