mailing list archives
Re: What do you want your ISP to block today?
From: "Gerardo Gregory" <ggregory () affinitas net>
Date: Sat, 30 Aug 2003 19:50:17 -0500
Well I understand why an ISP will filter these.
But those things you mentioned are not software vendor vulnerabilities, or
vulnerabilities of some proprietary protocol used only by desktop systems.
Also the ISP will filter anything it feels it is a threat to it's own
systems as that is where their own responsibility lies, and if they dont
protect these they dont make any money.
Because an ISP chooses to filter IANA reserved addresses (I am to argue that
all do not perform this type of filtering, I would think that applying
prefix lists, and null routes is what an ISP would do...not filter on source
address...I have received packets at my edge with a IANA reserved address as
the source), or turn off IP directed broadcasts, does not compare to
applying filters every single time some vendor releases faulty code, or
their code is exploited. These exploits affect the end user nodes of the
ISP's customer, not the ISP itself (in a grand scale). The ISP is a
Mark Borchers writes:
From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On
Behalf Of Gerardo Gregory
Frankly I dont want any of my ISP's filtering any of my
think we need (especially enterprise administrators like
myself) to take
some responsibility, and place our own filters.
That's a popular sentiment which derives its facade of reasonableness
from the notion that ISP's ought to provide unencumbered pipes to the
Internet core. However, it doesn't bear close scrutiny.
Would you say that ISP's should not filter spoofed source addresses?
That they should turn off "no ip directed broadcast"? Of course not,
because such traffic is clearly pathological with no redeeming social
The tough part for the ISP is to decide what other traffic types are
absolutely illegitimate and should therefore be subject to being
Verboten on the net.
Gerardo A. Gregory
Manager Network Administration and Security
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