Re: Puzzling NATD problem - revisited

2002-10-09 Thread Kim Helenius

Thank you both for your answers. The campus network uses public ip 
address space, sorry for not including that information. The fact why I 
included it in between the internet and the natd gateway is that if 
there's some weirdness in it, I somehow have to compensate for it in 
FreeBSD. As I stated, Linux users haven't had any problems with nat in 
the same network. Even I had working nat in the same network two years 
ago (on FreeBSD 4.1-4.3 I think) so I'm trying to pinpoint the cause for 
this extremely peculiar behaviour.

Josh Paetzel wrote:

On Tue, Oct 08, 2002 at 03:28:28PM -0400, JoeB wrote:
  

You state Network topology:
Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host

Internet is public ip address,  if Campus Network private ip address then
you can not nat them again, if Campus Network  is public ip address then  you
should nat x11 for the private ip address on the lan behind the FBSD box.


That's not correct.  I've seen two layers of NATD work just fine in an office 
building environment where the gateway to the office was natting ips to the 
individual clients, and then clients were natting again to hang multiple 
machines off the one ip they got from the office gateway.

Josh 
  

You should nat x11 for the private ip address on the lan behind the 
FBSD box.
I always thought natd should run on the external interface? How can natd 
work perfectly if I'm running it on a wrong interface?

  

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Kim Helenius
Sent: Tuesday, October 08, 2002 9:13 AM
To: [EMAIL PROTECTED]
Subject: Puzzling NATD problem - revisited

The setting:

Network topology:
Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host

A custom kernel build including the following options:
options IPFIREWALL
options IPDIVERT
Used the command:
sysctl net.inet.ip.forwarding=1
And started natd with natd -interface xl0

Then did, straight from the manpage, the following firewall rules:
/sbin/ipfw -f flush
/sbin/ipfw add divert natd all from any to any via xl0
/sbin/ipfw add pass all from any to any

Now NAT works perfectly for the internal host, but (almost) all TCP
connections cease to work to/from the NATD machine. AFAIK UDP and ICMP work
perfectly. I've tried this on two different FreeBSD machines in the same
network with identical results. If I remove the divert rule, everything
works perfectly, except of course for the NAT. There have been no similar,
puzzling effects on any Linux hosts I know of in the same network. Therefore
I'm sure there's some knob I haven't pushed yet :)

I'm aware this doesn't make much of a firewall but I'd like to get natd
working before I run the firewall script.

--
Kim Helenius
[EMAIL PROTECTED]



To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message


-- 
Kim Helenius
[EMAIL PROTECTED]


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message



RE: Puzzling NATD problem - revisited

2002-10-08 Thread JoeB

You state Network topology:
Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host

Internet is public ip address,  if Campus Network private ip address then
you
can not nat them again, if Campus Network  is public ip address then  you
should
nat  x11 for the private ip address on the lan behind the FBSD box.


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Kim Helenius
Sent: Tuesday, October 08, 2002 9:13 AM
To: [EMAIL PROTECTED]
Subject: Puzzling NATD problem - revisited

The setting:

Network topology:
Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host

A custom kernel build including the following options:
options IPFIREWALL
options IPDIVERT
Used the command:
sysctl net.inet.ip.forwarding=1
And started natd with natd -interface xl0

Then did, straight from the manpage, the following firewall rules:
/sbin/ipfw -f flush
/sbin/ipfw add divert natd all from any to any via xl0
/sbin/ipfw add pass all from any to any

Now NAT works perfectly for the internal host, but (almost) all TCP
connections cease to work to/from the NATD machine. AFAIK UDP and ICMP work
perfectly. I've tried this on two different FreeBSD machines in the same
network with identical results. If I remove the divert rule, everything
works perfectly, except of course for the NAT. There have been no similar,
puzzling effects on any Linux hosts I know of in the same network. Therefore
I'm sure there's some knob I haven't pushed yet :)

I'm aware this doesn't make much of a firewall but I'd like to get natd
working before I run the firewall script.

--
Kim Helenius
[EMAIL PROTECTED]



To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message


To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message



Re: Puzzling NATD problem - revisited

2002-10-08 Thread Josh Paetzel

On Tue, Oct 08, 2002 at 03:28:28PM -0400, JoeB wrote:
 You state Network topology:
 Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host
 
 Internet is public ip address,  if Campus Network private ip address then
 you
 can not nat them again, if Campus Network  is public ip address then  you
 should
 nat  x11 for the private ip address on the lan behind the FBSD box.

That's not correct.  I've seen two layers of NATD work just fine in an office 
building environment where the gateway to the office was natting ips to the 
individual clients, and then clients were natting again to hang multiple 
machines off the one ip they got from the office gateway.

Josh 


 
 -Original Message-
 From: [EMAIL PROTECTED]
 [mailto:[EMAIL PROTECTED]]On Behalf Of Kim Helenius
 Sent: Tuesday, October 08, 2002 9:13 AM
 To: [EMAIL PROTECTED]
 Subject: Puzzling NATD problem - revisited
 
 The setting:
 
 Network topology:
 Internet---Campus Network---(xl0)FreeBSD NATD machine(xl1)---Internal host
 
 A custom kernel build including the following options:
 options IPFIREWALL
 options IPDIVERT
 Used the command:
 sysctl net.inet.ip.forwarding=1
 And started natd with natd -interface xl0
 
 Then did, straight from the manpage, the following firewall rules:
 /sbin/ipfw -f flush
 /sbin/ipfw add divert natd all from any to any via xl0
 /sbin/ipfw add pass all from any to any
 
 Now NAT works perfectly for the internal host, but (almost) all TCP
 connections cease to work to/from the NATD machine. AFAIK UDP and ICMP work
 perfectly. I've tried this on two different FreeBSD machines in the same
 network with identical results. If I remove the divert rule, everything
 works perfectly, except of course for the NAT. There have been no similar,
 puzzling effects on any Linux hosts I know of in the same network. Therefore
 I'm sure there's some knob I haven't pushed yet :)
 
 I'm aware this doesn't make much of a firewall but I'd like to get natd
 working before I run the firewall script.
 
 --
 Kim Helenius
 [EMAIL PROTECTED]
 
 
 
 To Unsubscribe: send mail to [EMAIL PROTECTED]
 with unsubscribe freebsd-questions in the body of the message
 
 
 To Unsubscribe: send mail to [EMAIL PROTECTED]
 with unsubscribe freebsd-questions in the body of the message

To Unsubscribe: send mail to [EMAIL PROTECTED]
with unsubscribe freebsd-questions in the body of the message