On Wednesday 16 November 2005 07:30 pm, Daniel Hartmeier wrote: > On Thu, Nov 17, 2005 at 02:04:54AM +0100, Jonas Davidsson wrote: > > I found this in an old archive while I was in the midst of pulling > > my hair out trying to figure why synproxy refused to work for local > > services. This of course helped, (I put if-bound in the options for > > that individual rule) but why isn't this mentioned anywhere in the > > manual yet? > > I'm currently running OpenBSD 3.8-release. > > I guess it got lost. Since then, we added the 'set skip on lo' > feature (which is part of the example pf.conf), which resolves this > issue, and others. > > Instead of going into the gory details of how loopback filtering > breaks synproxy in this case, I think it would be better to simply > recommend skipping filtering on loopback, in general. The cases where > it's actually useful are equally technical. > > The man page in 3.8 contains this part > > set skip on <ifspec> > List interfaces for which packets should not be filtered. > Packets passing in or out on such interfaces are passed as if pf was > dis- abled, i.e. pf does not process them in any way. This can be > use- ful on loopback and other virtual interfaces, when packet > filtering is not desired and can have unexpected effects. For > example: > > set skip on lo0 > If that is the case, then a filter rule that says:
pass quick on lo0 all is essentially useless when the "set skip on lo" option is defined. Good this was brought up cos I have spotted both used in the same example.