On Jan 20, 2012, at 10:32 AM, Nikolay Denev wrote: > On Jan 15, 2012, at 9:52 PM, Nikolay Denev wrote: > >> On 15.01.2012, at 21:35, Andrey Zonov <and...@zonov.org> wrote: >> >>> This helped me: >>> /boot/loader.conf >>> net.inet.tcp.hostcache.hashsizee536 >>> net.inet.tcp.hostcache.cachelimit66080 >>> >>> Actually, this is a workaround. As I remember, real problem is in >>> tcp_ctlinput(), it could not update MTU for destination IP if hostcache >>> allocation fails. tcp_hc_updatemtu() should returns NULL if >>> tcp_hc_insert() returns NULL and tcp_ctlinput() should check this case >>> and sets updated MTU for this particular connection if >>> tcp_hc_updatemtu() fails. Otherwise we've got infinite loop in MTU >>> discovery. >>> >>> >>> On 15.01.2012 22:59, Nikolay Denev wrote: >>>> >>>> % uptime >>>> 7:57PM up 608 days, 4:06, 1 user, load averages: 0.30, 0.21, 0.17 >>>> >>>> % vmstat -z|grep hostcache >>>> hostcache: 136, 15372, 15136, 236, 44946965, >>>> 10972760 >>>> >>>> >>>> Hmm… probably I should increase this…. >>>> >>> >>> -- >>> Andrey Zonov >> >> Thanks, I will test this asap! >> >> Regards, >> Nikolay > > I've upgraded from 7.3-STABLE to 8.2-STABLE and bumped significantly the > hostcache tunables. > So far so good, I'll report back if I see similar traffic spikes. >
Seems like I have been wrong about these traffic spikes being attacks, and actually the problem seems to be the pmtu infinite loop Andrey described. I'm now running 8.2-STABLE with hostcache significantly bumped and regularly have more than 20K hostcache entries, which was more than the default limit of 15K I was running with before. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
