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Old 09-23-2005, 07:29 PM   #1
Registered: Oct 2004
Location: Australia, Brisbane
Distribution: Gentoo
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Question about DSL router and small internal network

My current setup is like this:

I have a ADSL modem/router, which is the Gateway to the internet. This has a public address that it gets dynamically from my ISP. Behind this is my Linux PC with a private ip address (192.168.X.X). Hence I am using NAT or IP Masquarading

When I do the All Port Scan test from this site (Shield Up - Is my ADSL router being tested here or my actual Linux box?

I think that it has to be my ADSL router that the test is applied too as this is the "face" to the internet - is this correct?

Old 09-23-2005, 07:37 PM   #2
Registered: Feb 2004
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Yes you are correct, it will be the router that is being tested as it has the public facing ip address being scanned on one of it's interfaces.

Unless of course it allows all incoming connections or something like that. I don't think any modern adsl router usually has a default configuration like that. Mine certainly doesn't.

If you really want to test you linux box in this way, you could investigate whether the router has a feature to forward all incoming connections to a particular internal host. The Linksys router I have has this feature, they call it a 'DMZ Host'.

Hope this helps,


Old 09-23-2005, 07:39 PM   #3
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Registered: Jan 2003
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The router is being tested from the outside to the wan port. I myself dislike the sheilds up site since it is out to sell products. Try this one for a better report.

You can use nmap to see what is open on your linux box. If you have another computer you can run port scanning software on it and use it to test your linux's internal IP.

Old 09-23-2005, 07:55 PM   #4
Registered: Oct 2004
Location: Australia, Brisbane
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Thanks Brian - good site that!


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