If your server are having multiple IP address and you want to send each emails in different IP, then please follow the steps. This is used to maintain the ip reputation. Also, please make sure that this is not used for spamming.

1. vi /etc/exim.conf
2. Search for the line : interface =
3. Replace this line with interface = xxx.xxx.x.1${eval:${substr{-2}{1}{$tod_zulu}}%9+1}
4. If your server is having ip’s from xxx.xxx.x.11 to xxx.xxx.x.20 , you can use above line.
+1 is is the starting ip ie xxx.xxx.x.1’1′ and %9 is the increment value ie 11(xxx.xxx.x.11) to how much. Here it is 20 (xxx.xxx.x.20)

If you require help, contact SupportPRO Server Admin