On Tue, 23 Dec 2003, Brett Glass wrote: > At 02:29 AM 12/23/2003, Mike Silbersack wrote: > > >I think that it might be best to keep choosing ports inside of libalias. > >Adding yet another port range would just complicate the kernel more > >without much benefit. > > Actually, it would just change the code in libalias. It wouldn't > change the kernel at all, except that it would make two 16-bit > unsigned quantities available to libalias. (These variables > might be instanced in jails, by the way.)
Ah, so you want a central location for all users of libalias to pull settings from. I think that might be better served by a /etc/libalias.conf or something. > Hmmm.... If you want to do this, It might be better to make a global > bitmap whose contents are set by whatever firewall is in operation (IPFW, > ipf, pf) and then masked by allowed port ranges. This would be a simple, > fixed overhead operation. And it would probably speed the random, > nondeterministic process via which libalias currentl picks a port. Yes, > it'd waste some ports if you had snaky firewall rules that only sometimes > blocked a port. But it's not worth the time it would take to test all the > rules, which might depend on src/dst addresses, etc. > > --Brett The problem is that a bitmap is really too simplistic, because you might allow certain ports to certain IPs and not others. I don't think the overhead of checking ipfw would be too great, considering that every packet would normally go through all those rules anyway; my concern is simply that ipfw / ipf do not have a "test" function that will run without a real packet being passed. Well, in any case, I don't have time to work on this project anytime soon. If one of you guys can come up with some relatively simple solution to the problem (perhaps some simple comma-delimited sysctl which lists ports to deny) that works, I'd be happy to look into merging it. Mike "Silby" Silbersack _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
