Date: Sun, 8 Jul 2001 17:57:52 -0400 (EDT) From: Kenneth Wayne Culver <culverk@wam.umd.edu> To: freebsd-hackers@freebsd.org Subject: NAT (ipf/ipnat) latency problems Message-ID: <Pine.GSO.4.21.0107081738150.23241-100000@rac3.wam.umd.edu>
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Recently over the weekend my friends and I had a lanparty, and we wanted to use FreeBSD as his gateway machine (to replace Win2k) to his cable modem. When I got there, he and 3 other people had been playing a game online (over the internet through the Win2k NAT, the game was counterstrike for those who care) and they were seeing really good pings and no packet loss (pings of 15-39ms). I set up the FreeBSD server (which I had already preconfigured for the task) using ipf and ipnat with very simple rules (ipf passes all traffic in and out, and map 192.168.0.0/28 -> 0/32 portmap 20000:40000 as the ipnat rule. The portmap is so that multiple people from our lan can connect to the same counterstrike server). I pinged the counterstrike server online from our NAT machine and the NAT machine got 15-30ms pings, but when I went online in counterstrike and went to that server, the ping was about 200 ms, and if more than 2 people connected to any counterstrike server at a time, the ping went up to 1500-2000 ms. I read about some settings to the kernel's timecounters that might fix the problem, so I rebuilt a kernel with the HZ=1000 option and rebooted the router. We still had the same problem, so I tried using natd and ipfw. This was even slower. My question is: why could 4 people total connect through a win2k NAT server (using 2 3com 90x 10/100 cards, and a 933MHz PIII) through the same server, and maintain a 15 - 30 ms ping and no packet loss, when with FreeBSD using an 800 MHz athlon with 2 DEC 21140A ethernet cards, or with 2 intel (fxp) cards (we tried both) we maxed out at 2 people connected to that same server we got a lot of packet loss and really high (200-2000ms depending on how many people are connected )??? Thanks a lot ... Kenneth Culver To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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