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Date: Tue, 3 Dec 1996 12:35:53 -0600 (CST)
From: Mark Tinguely <tinguely@plains.nodak.edu>
Message-Id: <199612031835.MAA11050@plains.nodak.edu>
To: freebsd-questions@freebsd.org
Subject: NAT/pppd problem revisited
Sender: owner-questions@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk


I am having problems setting NAT, I removed the Cisco Terminal Server
for experiments, now I have:

	FreeBSD 2.1.5-RELEASE #1
	ed0 10.1.0.3/255.255.255.0

		^^
		||
		||
		||
		vv

	ed0 10.1.0.2/255.255.255.0
	FreeBSD 2.1.5-RELEASE #2 (ip_fil3.0, gateway enabled)
	ppp0 10.1.10.2/255.255.255.0

		^
		|
		|
		|
		v

	ppp0 10.1.10.1/255.255.255.0
	FreeBSD 2.1.5-RELEASE #3


I run tcpdump on port host
		 ed0  #1
		 ed0  #2
		 ppp0 #2
		 ppp0 #3

I use NAT translations of:

map ppp0 10.1.0.3/32 -> 10.1.10.2/32 portmap tcp 1025:20000
					     ^^^
		note: I can't get ipnat to take "tcp/udp"

the ppp0 tcpdumps for a telnet from 10.1.0.3 (#1) to 10.1.10.1 (#3) sees:
12:26:58.337540 10.1.10.2.1026 > 10.1.10.1.23: S 1285952001:1285952001(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 20075 0,nop,nop,ccnew| (DF) [tos 0x10]
12:27:04.053407 10.1.10.2.1026 > 10.1.10.1.23: S 1285952001:1285952001(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 20086 0,nop,nop,ccnew| (DF) [tos 0x10]
12:27:28.047110 10.1.10.2.1026 > 10.1.10.1.23: S 1285952001:1285952001(0) win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 20134 0,nop,nop,ccnew| (DF) [tos 0x10]

so I know NAT on #2 did translate the 10.1.0.3 address to a 10.1.10.2 address
but there something about that packet that #3 does not respond.

netstat -i counts these packets but reports no errors.

any ideas?

--mark.