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Re: Port blocking last resort in fight against virus
From: Mans Nilsson <mansaxel () sunet se>
Date: Tue, 12 Aug 2003 17:50:38 +0200

Subject: Re: Port blocking last resort in fight against virus Date: Tue, Aug 12, 2003 at 10:36:12AM -0500 Quoting Jack 
Bates (jbates () brightok net):

Is it just me that feels that blocking a port which is known to be used 
to perform billions of scans is only proper? It takes time to contact, 
clean, or suspend an account that is infected. Allowing infected systems 
to continue to scan only causes problems for other networks. I see no 
network performance issues, but that doesn't mean other networks won't 
have issues.

I have two faces, let's hear what they say:

"I am a network operator. I do not see issues with my network unless
 somebody fills it up beyond capacity. Then I might ask somebody a
 question as to why they are shoveling so many more packets than
 usual. If it is a panic, I might null0 someone. I just want to keep
 my network transparent."

"I am a systems administrator. Sometimes, there are security problems with 
 my operating systems of choice. Then, I fix those hosts that are affected,
 and all is well. The network is not bothering me as long as it is 
 transparent." 

Your chosen path is a down-turning spiral of kludgey dependencies,
where a host is secure only on some nets, and some nets can't cope
with the load of all administrative filters (some routers tend to
take port-specific filters into slow-path). That way lies madness. 

-- 
Måns Nilsson         Systems Specialist
+46 70 681 7204         KTHNOC
                        MN1334-RIPE

Oh my GOD -- the SUN just fell into YANKEE STADIUM!!

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