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Hi,

I've looked at Google but the hints I found didn't work i.e.,
setting net.inet.tcp.1323=3D0. AFAICS every other server works quite fine
but e.g., www.netbsd.org insists on sending too large packets. I have
a ADSL account using PPPoE with a MTU of 1452 for pppoe0. I have now
problems from the directly connected "router" but the NATed host
can't receive data from *.netbsd.org. However, it works if I decrease
the mssclamp parameter to 1412 in /etc/ipfnat.conf. Anyway, I don't
see what's so special about netbsd.org.

Here's a tcpdump log from a connection attempt with Mozilla to
http://www.netbsd.org/:

15:47:18.424840 PPPoE  [ses 0x560] IP 54: cyclonus.40044 > www.netbsd.org.w=
ww: F 3594670041:3594670041(0) ack 3662811147 win 33580 <nop,nop,timestamp =
80 424894> (DF)
15:47:18.654277 PPPoE  [ses 0x560] IP 54: www.netbsd.org.www > cyclonus.400=
44: . ack 1 win 33580 <nop,nop,timestamp 424975 80>
15:47:20.196956 PPPoE  [ses 0x560] IP 62: cyclonus.40052 > www.netbsd.org.w=
ww: S 728649424:728649424(0) win 32768 <mss 1452,nop,wscale 0,nop,nop,times=
tamp 0 0> (DF)
15:47:20.519320 PPPoE  [ses 0x560] IP 62: www.netbsd.org.www > cyclonus.400=
52: S 2449916058:2449916058(0) ack 728649425 win 32768 <mss 1460,nop,wscale=
 0,nop,nop,timestamp 424978 0>
15:47:20.522137 PPPoE  [ses 0x560] IP 54: cyclonus.40052 > www.netbsd.org.w=
ww: . ack 1 win 33580 <nop,nop,timestamp 1 424978> (DF)
15:47:20.523000 PPPoE  [ses 0x560] IP 526: cyclonus.40052 > www.netbsd.org.=
www: P 1:473(472) ack 1 win 33580 <nop,nop,timestamp 1 424978> (DF)
15:47:20.785731 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5407:24@0+)
15:47:20.803033 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5407:1456@24)
15:47:20.803095 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5408:24@0+)
15:47:20.804005 PPPoE  [ses 0x560] IP 42: cyclonus.40053 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)
15:47:20.819778 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5408:1456@24)
15:47:20.819839 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5409:24@0+)
15:47:20.820275 PPPoE  [ses 0x560] IP 42: cyclonus.40053 > www.netbsd.org.6=
: R 0:0(0) ack 1435 win 0 (DF)
15:47:20.836357 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5409:1456@24)
15:47:20.836418 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5410:24@0+)
15:47:20.836848 PPPoE  [ses 0x560] IP 42: cyclonus.40053 > www.netbsd.org.6=
: R 0:0(0) ack 4294967291 win 0 (DF)
15:47:20.852873 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5410:1456@24)
15:47:20.853434 PPPoE  [ses 0x560] IP 42: cyclonus.40053 > www.netbsd.org.6=
: R 0:0(0) ack 1 win 0 (DF)
15:47:22.015171 PPPoE  [ses 0x560] IP 526: cyclonus.40052 > www.netbsd.org.=
www: P 1:473(472) ack 1 win 33580 <nop,nop,timestamp 4 424978> (DF)
15:47:22.126176 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5417:24@0+)
15:47:22.144106 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5417:1456@24)
15:47:22.145116 PPPoE  [ses 0x560] IP 42: cyclonus.40054 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)
15:47:22.268826 PPPoE  [ses 0x560] IP 54: www.netbsd.org.www > cyclonus.400=
52: . ack 473 win 33580 <nop,nop,timestamp 424982 1>
15:47:24.626470 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
06: . [bad hdr length] (frag 5440:24@0+)
15:47:24.643768 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5440:1456@24)
15:47:24.644725 PPPoE  [ses 0x560] IP 42: cyclonus.40055 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)
15:47:25.140841 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5457:24@0+)
15:47:25.158219 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5457:1456@24)
15:47:25.159392 PPPoE  [ses 0x560] IP 42: cyclonus.40056 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)
15:47:28.633297 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
10: . [bad hdr length] (frag 5495:24@0+)
15:47:28.649223 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5495:1456@24)
15:47:28.650203 PPPoE  [ses 0x560] IP 42: cyclonus.40057 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)
15:47:31.126158 PPPoE  [ses 0x560] IP 46: www.netbsd.org.www > cyclonus.400=
52: . [bad hdr length] (frag 5517:24@0+)
15:47:31.143534 PPPoE  [ses 0x560] IP 1478: www.netbsd.org > cyclonus: tcp =
(frag 5517:1456@24)
15:47:31.144443 PPPoE  [ses 0x560] IP 42: cyclonus.40058 > www.netbsd.org.6=
: R 1213486160:1213486160(0) win 0 (DF)

Port 6 and "bad hdr length" looks pretty strange to me. And why does it
keep sending IP packets of 1478 octets?

This is my /etc/ipnat.conf:
map pppoe0 cyclonus/32 -> 0/32 portmap tcp/udp 40000:58000 mssclamp 1452
map pppoe0 cyclonus/32 -> 0/32 mssclamp 1452

rdr rtk0 shockwave/32 port 53 -> $DNS1,$DNS2 port 53 udp
rdr rtk0 shockwave/32 port 53 -> $NTP port 53 udp

I've experienced this problem before but simply gave up and reduced my
MTU - I don't think this is *the* solution.

--=20
Christian
=20
As you can see, this a signature. It's not related to the contents of the
mail in any way. But you probably won't listen to me anyway, will you?

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