[ale] Comcast: can get out but not in

[James P. Kinney III]

On Mon, 2006-09-18 at 13:17 -0700, Steven A. DuChene wrote:
> Jim:
> Thanks for the questions.
> There is nothing except a network cable between the system
> and the cable modem. I had my non-technical friend on-site
> double check the IP address showing up on the system and
> it was indeed the exact one I was trying to connect to.

There must be some sort of firewall code in the cable modem that blocks
incoming "connect" requests.

Check your gateway address, disconnect the cable feed from the cable
modem and ping the gateway address. If you get a reply, the cable modem
is at least semi-smart. Reconnect the cable feed and then from the
outside, nmap the gateway address. If you can, setup another system on a
hub between the cable modem and your box. Give an address like the real
address but off by one or so (watch out for duplicate IP address
warnings and change it quickly so you won't mess up someone else). Now
nmap your box from the new machine. You can also run tcpdump on the new
machine and see what goes by on the wire.

-- 
James P. Kinney III          
CEO & Director of Engineering 
Local Net Solutions,LLC        
770-493-8244                    
http://www.localnetsolutions.com

GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
<jkinney at localnetsolutions.com>
Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7
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