Weird double NAT issue

Noah January 30, 2009 at 13:51:25
Specs: Macintosh
I seem to have a double NAT issue that i discovered when
trying to open some ports. I live rent a room that includes
internet, so I'm not entirely aware of what's on the
network elsewhere in the house. But doing a trace route
reveals two routers:

I asked my landlord if he had two routers attached to one
another and he said no. I tend to believe him because I
once took a look at the router myself when helping him
with a computer.

One of the routers also happens to be one used for VOIP,
according to what I've read, but he does not use VOIP.

I suspect that someone else in the building is could be
using VOIP. But why would my connection be going
through that router? Is that what happens when a router is
attached to a network already with a router?

There must be a way to bypass the other router or
something. The passwords are all default, so I have access
to both routers. I tried making the one a
switch (by changing the mode), but the internet dies when
I do so.

Any ideas or insight would be a big help!

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January 30, 2009 at 15:00:21
If you have access to the 2nd router as well, why not open ports on it too.


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January 30, 2009 at 15:54:51
rais' suggestion, which for example, if you wanted to forward port 80 to a computer on your network, would mean you could;
- on the router, forward port 80 to whatever IP address is on your router's WAN side.
- Then forward port port 80 on your router to whatever computer is on your local network, say

But that can be kind of messy and sometimes communications have problems going through two firewalls.

What may have happened is your landlord may not have realized that the Internet modem may also be acting as a router, then he attached another router to it not realizing the modem was also acting as a router.

To know fore sure, your going to have to follow the wires from router to router to modem.

Assume that I already did an Internet search.

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