What is an Exim iplsearch file?

Question

What is an Exim iplsearch file?

Answer

Sometimes you will want to have Exim search for data, but you don't want that stored in the exim.conf file. You can use a file for this, and then manually create a file with your list of data.

For example, this may be in your exim.conf file:

CONFIG_TEXT: smtp_accept_max_per_host = ${lookup{$sender_host_address}
iplsearch{/etc/mycustomfile}}

You can create mycustomfile with the data, and it will be read by Exim.

The structure of the data within the file has a specific format:

CONFIG_TEXT: key: data 

The key for an iplsearch lookup must be an IP address (without a mask). The file is searched linearly, using the CIDR masks where present, until a matching key is found. The first key that matches is used; there is no attempt to find a "best" match.

For further information, please review the Exim documentation:

Exim | File and database lookups