Since upgrade to version 1.580, Webmin can't resolve the hostname in the IP-Access-Control Module ... If I say: allow only *.dip.blah.net (which is the resolve of my actual ip), webmin tells me it won't work cause I'm getting blocked!
So, this function is uselss now. In Usermin everythings working and BEFORE the upgrade to 1.580 it worked (over years!!!) in webmin too. No other OS related things changed.