Date: Tue, 16 Jan 2007 09:37:51 +0800 From: "fooler" <fooler@skyinet.net> To: <freebsd-net@freebsd.org> Subject: Re: Problem with port 0 Message-ID: <046d01c7390e$efa9da80$42764eca@ilo.skyinet.net> References: <f9876c510701120903r65543ef4nafc7eeead2becb42@mail.gmail.com> <eog1q1$r89$1@sea.gmane.org>
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Hug Me wrote: > 11:08:06.528691 IP (tos 0x4, ttl 255, id 0, offset 0, flags [DF], length: > 51) 10.0.0.2.0 > 10.0.0.1.69: [udp sum ok] 23 RRQ "load2000v115.d" octet > > We believe FreeBSD is not allowing a UDP source port of 0 and the kernel > is > dropping the packet before it ever reaches the tftp server but are > unable to > verify this hypothesis. im using carp for highly availability and scalability with the help of layer 4 health check program that i made using source port 0 both for tcp and udp protocols.... sample of tcpdump output from my layer 4 health check program... [root@proxy1r fooler]#tcpdump -i lo0 -n tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo0, link-type NULL (BSD loopback), capture size 96 bytes 09:25:22.913088 IP 127.0.0.1.0 > 127.0.0.1.3128: S 0:0(0) win 65535 09:25:22.913111 IP 127.0.0.1.3128 > 127.0.0.1.0: S 3117019729:3117019729(0) ack 1 win 64240 <mss 16344> 09:25:22.913121 IP 127.0.0.1.0 > 127.0.0.1.3128: R 1:1(0) win 0 09:25:22.923064 IP 127.0.0.1.0 > 127.0.0.1.53: [|domain] 09:25:23.934176 IP 127.0.0.1.0 > 127.0.0.1.3128: S 0:0(0) win 65535 09:25:23.934198 IP 127.0.0.1.3128 > 127.0.0.1.0: S 816240627:816240627(0) ack 1 win 64240 <mss 16344> 09:25:23.934208 IP 127.0.0.1.0 > 127.0.0.1.3128: R 1:1(0) win 0 09:25:23.934222 IP 127.0.0.1.0 > 127.0.0.1.53: [|domain] when proxy is alive (tcp port 3128) it will reply with syn/ack and i reply it with reset.. when dns is alive (udp port 53)... the server wont reply anything (and that is normal for udp).... but when proxy is dead... it will reply with reset.... when dns is dead.. it will reply with icmp port unreachable... this simply shows that source port 0 both for tcp and udp work properly with freebsd... fooler.
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