TCP/IP FIltering

[LFreak]

I have to configure a server to allow only smtp connection, 25.

I have tried to use ip filtering in windows 2000, but it blocked all port and i can't even ping.

I know that i have to enable port 25 and port 53 for dns,

have i missed something else here

 

[RyanS]

When you enable IP filtering it denies everything by default. You have to manually allow ports/protocols as needed. IIRC there is an allow column for UDP & TCP which you will want to select for those ports.

 

[LA1]

if you are going onto the internet you may also have to enable port 113, ident, you maybe able to get away with out. If you go to many sites and the sites never responds try enabling port 113.

 

[LFreak]

what are the required ports that i should enable, the server should not be able to communicate to the internet

i have enabled tcp port 25 n 53

n disabled all others, any more port to enable.

coz the server can't send the mails

 

[LA1]

port 110 pop3 , that is inbound

go to shields up to test

https://www.grc.com/x/ne.dll?bh0bkyd2

 

[LFreak]

well i got the answer to to it

with tcp/ip filtering, you can only filter inbound packet not outbound,

for outbound you need to use a third party software or use ipsec policies