ISP port blocking practice

Thu Oct 22 21:37:03 UTC 2009

On Thu, 22 Oct 2009 13:22:17 -0400, Zhiyun Qian <zhiyunq at umich.edu> wrote:
> 1). For any outgoing traffic, if the destination port is 25, then drop  
> the packets.
> 2). For any incoming traffic, if the source port is 25, then drop the  
> packets.

Inspecting outgoing traffic is generally easier to do as there's less of  
it. (in a consumer context, which is the only place such filtering makes  
any sense.)

--Ricky