And a third answer! I’ve mentioned TagMatch before - https://github.com/fmbla/spamassassin-tagmatch
From https://spamassassin.apache.org/full/3.4.x/doc/Mail_SpamAssassin_Conf.html#template_tags ifplugin Mail::SpamAssassin::Plugin::Tagmatch tagmatch __TAGMATCH_RDNS_AWS _LASTEXTERNALRDNS_ =~ /\.amazonaws\.com$/ meta LOCAL_AWSURI __TAGMATCH_RDNS_AWS score LOCAL_AWSURI 2.6 describe LOCAL_AWSURI Last rDNS amazonaws.com endif I find .compute.amazonaws.com a good indicator Paul On 18/01/2017, 17:13, "Ken Johnson" <kjohn...@eclypse.org> wrote: Hi, I would like to write a rule to compare the rDNS lookup of the sender's IP address to a regular expression. I have written super simple URI rules for /etc/spamassassin/local.cf (Debian Linux system) like this: uri LOCAL_AWSURI /.*amazonaws\.com/ score LOCAL_AWSURI 2.6 describe LOCAL_AWSURI Links to site at amazonaws.com which work as expected. But my Google searches for examples or discussion must be the wrong search terms, as the search results are about other topics, not the one I want. Can someone provide an example or point me toward documentation of how to write such a rule? Thanks, Ken -- Paul Stead Systems Engineer Zen Internet