Currently the 'host allow' configuration option does a reverse lookup.
It would be more useful if rsync could do a forward look up of the host and match the IP Address agains the look host name.
This allows for the rsync directory to be secured via a service such as no-ip.com.
Created attachment 2961 [details]
Patch to 2.6.9 to allow forward host name lookup as described
I have created an official patch based on your work:
I will be considering this for inclusion in the main release.
Support for this has been added to the 3.1.0dev source. A config item to disable forward lookups (on a per-module basis) was also added.