nanog mailing list archives

Re: ISP port blocking practice


From: "James R. Cutler" <james.cutler () consultant com>
Date: Fri, 23 Oct 2009 19:33:58 -0400

No, blocking a port does not restrict a customers use of the network any more than one way streets restrict access to downtown stores. It just forces certain traffic directions in a bicycle/motorcycle/car/van/ truck neutral manner. Carry anything you want. Others laws restrict incendiary content.


On Oct 23, 2009, at 6:15 PM, Dan White wrote:

On 23/10/09 17:58 -0400, James R. Cutler wrote:
Blocking the well known port 25 does not block sending of mail. Or the
message content.

It does block incoming SMTP traffic on that well known port.

I think the relevant neutrality principle is that traffic is not blocked
by content.

My personal definition doesn't quite gel with that. You're deciding for the customer how they can use their connection, before you have any evidence of
nefarious activity.

Would you consider restricting a customer's outgoing port 25 traffic to a
specific mail server a step over the net neutrality line?

--
Dan White

James R. Cutler
james.cutler () consultant com






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