Max Laier wrote: > On Friday 25 January 2008, Stefan Lambrev wrote: > >> Greetings, >> >> Does anyone try to see PF with "keep state" in action when under syn >> flood attack? >> I tried to get some help in freebsd-pf_at_, because the test firewall, >> that I build hardly can handle 2-5MB/s syn flood. >> Unfortunately I do not saw useful advice. >> The problem is that a quad core bridge firewall running freebsd 7 amd64 >> with PF is near useless and can't handle "small" SYN ddos. >> >> Here is the schema that I'm testing: >> web server (freebsd) - freebsd (bridged interfaces) - gigabit switch - >> clients + flooders >> In this configuration ~25MB/s syn flood (and I think this limit is >> because of my switch) is not a problem and the web server responds >> without a problem. >> With this configuration netperf -l 610 -p 10303 -H 10.3.3.1 shows >> 116MB/s stable speed , so I guess there are no problems with cables, >> hardware and etc :) >> >> But when I start pf (see below the config file) the traffic drops to >> 2-3MB/s and the web server is hardly accessible. >> It seems that device polling helps a lot in this situation, and at >> least the bridge firewall is accessible. Without "polling" the firewall >> is so heavily loaded >> that even commands like "date" take few seconds to finish, with 2 cores >> at ~100% idle at same time. >> >> I have "flat profiles" from hwpmc, and I think it indicates a problem: >> >> (bridge, pf enabled, polling enabled, sched_ule - I have profiles and >> for other combinations too if needed) >> % cumulative self self total >> time seconds seconds calls ms/call ms/call name >> 24.0 268416.00 268416.00 0 100.00% _mtx_lock_sleep >> > > Can you build a kernel with LOCK_PROFILING and try to figure out which > lock is causing this? > Yes I can build kernel with LOCK_PROFILING. But I have no idea how to use it :) Can you point me to some documentation?Received on Sat Jan 26 2008 - 20:00:04 UTC
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