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Trick about the Access-List

Dear My reader,

I have this idea in my mind, and i am searching for your advice, in order to go ahead and implement it or stop even thinking about it.

the idea is :-

My mail server is hosted in my isp side, and inside my company here i do not have any internal mail server at all, for any communications going on .

all the users used to use the POP3 Account and using the SMTP account to send / receive E-mails.

the only thing which is worest is ,if i have no internet, i will be unable completely to send / receive any E-mails from outside at all.

now, imagine MY SMTP SERVER WAS .

( This is Public IP ).

and MY POP3 Server was

( This is Public IP ) .

and my doamain was XYZ.COM .


Now, here is my question,

can i add or write an Access-list to Deny for example user who is his E-mail ( within my doamin ) like:-

SAM @ from sending any E-mails at all to another user in the same Domain like ( AHMED @ ) .


my question is, can i implement this idea, in stead of write an access-list to deny or permit the POP3 or SMTP completely for this User ?

i need to do this on one of my users inside my LAN.

he is using POP3 account and he is connected to the Internet through my Router.

so Please guys, can any one tell me how to implement this idea if its possible ?


Re: Trick about the Access-List


As far as I am concerned, you cannot filter/block user (with username/domain name) using ACL.

ACL is specifically meant to filter source/destination IP with source/ destination port.

I believed your idea can be implemented on the server-side (application).