Block a sender

Question

Hi Jay,
How to deny a specific address (outside my domain) to send emails to my users?
I know it can be done from FROM_ACCESS, but can you please give me the exact syntax such as:
*|*|*|*|<The_External_Address>|* $NRelaying$ Not$ Allowed!
Will this work?
thanks,

Answer 1

Hi Linda,
An example of testing a mapping table rule is as follows:
bash-2.05# ./imsimta test -mapping
Enter table name: ORIG_SEND_ACCESS
Input string: tcp_local|[email protected]|tcp_local|[email protected]
Output string: 30|Relaying not allowed
As the input string you need to provide the values that are to be tested (not just the address, but in this case also the incoming channel, outgoing channel and rcpt to: address)
For your filter, you probably want to have something like:
tcp_local|[email protected]|*|* $N$D30|Blocked$ address$ go$ away
The $N will cause the email to be rejected before it is accepted, therefore you don't need to worry about having to process the bounce. The $D30 also causes a 3 second delay before the rejection occurs; this slows down the sender (punishes them you might say).
With regards to an external file, what you should be using is the general db callout (which is nice and fast).
Three files at the following site should help you with this:
http://ims.balius.com/resources/downloads/index.html
general.txt (source file for the general database, this is where you put the address to be rejected)
spam-update.sh (script to create the general database file from the general.txt source, the general db file is what message server looksup)
mappings.txt (the mappings file which has the general database callout)
Hope this helps.
Shane.