Currently, rsyslog's mmanon module has the task of anonymizing ip-addresses. However, due to only being able to anonymize ipv4-addresses, I decided to overhaul the module to be able to also work with ipv6-addresses (see this feature request). In doing this, I also noticed some bugs with the ipv4-module.
Now there are two options: try to fix these or rewrite the function. While it might seem like more work, I have decided to rewrite the function, since I was already planning to add new configuration options like the option to randomize ip-addresses.
I have already worked on a similar tool for liblognorm which has never been released due to a lack of time on my part. An UNFINISHED VERSION of this work is available in my private repository.
Since this function already has some of the options I plan to implement, I will implement this as part of the new mmanon ipv4 anonymization.
But what about the current options? I will try to implement as many as possible in the initial rewrite, however some may be up for later reintroduction since I also plan on starting with the ipv6 anonymization as soon as possible. However I think that not too many people were using the module and consequently, its options. At least searching the github issue tracker for mmanon did not bring up many issues. Most of them not even really related to mmanon. There are also only few questions regarding mmanon on the mailing list. I think this proves my point, since some of the bugs affect major parts of the function.
If you were using or are currently using the module, I would be glad if you could tell me what configurations you are using and what is important to you when using the module. I have created a github issue tracker for this purpose.