RE: Help with port forwarding

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It's already in the script and I've checked several times.  
Thanks for trying, though.

> -----Original Message-----
> From: Alistair Tonner [mailto:Alistair@xxxxxxxxxx]
> Sent: Friday, October 24, 2003 1:05 PM
> To: Kleiner, Peter; 'netfilter@xxxxxxxxxxxxxxxxxxx'
> Subject: Re: Help with port forwarding
> 
> 
> On October 24, 2003 09:34 am, Kleiner, Peter wrote:
> 
> 	Just a bizarre thought, since you seem to be looking at 
> forwarded traffic not 
> 	getting out .. .did you check 
> /proc/sys/net/ipv4/ip_forward to ensure it 
> exists on PC2 and contains 1? -- not sure why but I have seen 
> an install 
> where it did NOT exist.  -- rebuilt the kernel to fix it .. 
> .so I suppose the 
> kernel that was in place was not properly configured. 
> *shrugs* ... I'm only 
> asking since it wasn't said.. and sometimes the simple answer 
> is the fast 
> one.
> 
> 
> > Thus spake Mark E. Donaldson:
> > > Peter - I don't see anything obvious in the script that could be
> > > problematic.  What do you mean by "port forwarding not
> > > working"?
> >
> > When I run the script as shown, I can telnet through any of 
> the filtered
> > ports (110, 143, 443) on the working PC, but not on the 
> not-working PC.
> >
> > > Are you
> > > getting any error messages?
> >
> > None whatsoever.  I tried logging the traffic, but nothing 
> showed up.
> > Interestingly, when I had logging on, it showed various attempts at
> > port 135:
> > Oct 21 16:55:45 gw kernel: IN=eth1 OUT=
> > MAC=00:30:21:07:ef:94:00:02:b9:91:7d:40:08:00 SRC=63.67.218.114
> > DST=XX.XX.4.7 LEN=64 TOS=0x00 PREC=0x00 TTL=115 ID=44619 DF 
> PROTO=TCP
> > SPT=4168 DPT=135 WINDOW=64240 RES=0x00 SYN URGP=0
> > Oct 21 16:55:46 gw kernel: IN=eth1 OUT=
> > MAC=00:30:21:07:ef:94:00:02:b9:91:7d:40:08:00 SRC=63.67.218.114
> > DST=XX.XX.4.7 LEN=64 TOS=0x00 PREC=0x00 TTL=115 ID=44889 DF 
> PROTO=TCP
> > SPT=4168 DPT=135 WINDOW=64240 RES=0x00 SYN URGP=0
> > Oct 21 16:55:46 gw kernel: IN=eth1 OUT=
> > MAC=00:30:21:07:ef:94:00:02:b9:91:7d:40:08:00 SRC=63.67.218.114
> > DST=XX.XX.4.7 LEN=64 TOS=0x00 PREC=0x00 TTL=115 ID=45129 DF 
> PROTO=TCP
> > SPT=4168 DPT=135 WINDOW=64240 RES=0x00 SYN URGP=0
> > Oct 21 16:59:23 gw kernel: IN=eth1 OUT=
> > MAC=00:30:21:07:ef:94:00:02:b9:91:7d:40:08:00 SRC=66.156.169.85
> > DST=XX.XX.4.7 LEN=48 TOS=0x00 PREC=0x00 TTL=112 ID=47221 DF 
> PROTO=TCP
> > SPT=2180 DPT=135 WINDOW=16384 RES=0x00 SYN URGP=0
> > Oct 21 16:59:24 gw kernel: IN=eth1 OUT=
> > MAC=00:30:21:07:ef:94:00:02:b9:91:7d:40:08:00 SRC=66.156.169.85
> > DST=XX.XX.4.7 LEN=48 TOS=0x00 PREC=0x00 TTL=112 ID=47351 DF 
> PROTO=TCP
> > SPT=2180 DPT=135 WINDOW=16384 RES=0x00 SYN URGP=0
> > [sorry for the long text lines]
> > But nothing was recorded when I tried to telnet to ports 
> 110, 143 or 443.
> >
> > > Is translation being performed
> > > but the packets
> > > are not routed?
> >
> > I'm not sure how to tell that.  Possibly.  Running nmap of 
> the public
> > address shows:
> > Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
> > Interesting ports on  (XX.XX.4.7):
> > (The 1596 ports scanned but not shown below are in state: closed)
> > Port       State       Service
> > 22/tcp     open        ssh
> > 25/tcp     open        smtp
> > 110/tcp    filtered    pop-3
> > 143/tcp    filtered    imap2
> > 443/tcp    filtered    https
> >
> > > I might be able to generate some ideas here
> > > if you can be
> > > more specific.
> >
> > Please let me know what else you need.  I am completely 
> baffled.  Why would
> > the same
> > script work on one machine and not the other?  That is why 
> I listed the
> > lsmod in my
> > original post.  I wonder if it's something not related to 
> iptables.....?
> >
> > > By the way, I believe you are meaning to
> > > block the Auth
> > > protocol (port 113):  that being the case, you need to
> > > specify TCP and not
> > > UDP.
> >
> > Fixed.  Thanks!
> >
> > Pete
> 
> -- 
> 
> 	Alistair Tonner
> 	nerdnet.ca
> 	Senior Systems Analyst - RSS
> 	
>      Any sufficiently advanced technology will have the 
> appearance of magic.
> 	Lets get magical!
> 


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