[c-nsp] ISP POP Location - Blocking Ports - Advice

[joshua sahala]

On (02/08/04 21:14), Paul Stewart wrote:
> 
> What I am wondering though is what ports are commonly blocked now on ISP's?
> Anyone care to share their lists?
> 

it depends - do your users know that you are going to do this? ;)
customers can get mad if their favorite windows app breaks because you
filtered it (no matter how many good reasons there are for it to be
filtered).
that being said:  i do no customer filtering at my current employer
unless they ask.  as my previous employer, we filtered a lot of
services, mostly because they resold those services downstream as
'premium offerings' (i just provided them transit).  on my lan i
filter tcp/udp 135-139 & 445, plus outbound smtp not coming from my
mail servers.  it there is some new worm, i might filter that because
my users like to open the secret attachment from the friend they have
never met ;)

/joshua
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