nanog mailing list archives

Re: BCP for ISP to block worms at PEs and NAS


From: Randy Bush <randy () psg com>
Date: Sun, 17 Apr 2005 06:25:45 -1000


On my Cisco-based SP network with RPMs in MGX chassis acting as
PEs: I have the ACL below applied on many network devices to
block the common worms ports,
if you are a service provider, perhaps filtering in the core
will not be appreciated by some customers.  of course, as a
provider, you can choose what 'service' you are providing.  but,
if you filter ports, it is not clear you are providing internet
service.
one approach might be radius installed filters? some contract
language to allow 'customers' to request standard templated
filters at little/no-extra cost to them. Allow them to make the
decision to filter themselves (where 'themselves' may be a dial
reseller, of course).  Making them responsible means when
odd-application-12 comes along to utilize tcp/135 you won't have
to poke spot holes through your filters to permit this access.

yep.  but note that kim says "ACL below applied on many network
devices," and went on to mention ras, which i, possibly mistakenly,
took to mean not just the radius-able edge.

randy


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