Sounds more like a browser issue than the router, if it was giving out
bad addresses you'd not be able to connect to the internet with it !

Try downloading a different browser ( Opera / Chrome etc ) and see if
they have the same problem.

I have opera, chrome & ff and they are all doing it.
And, they are doing it also on my xp laptop.
I feel like Ive been hi-jacked!

If it's also the same on a different PC then the only option does
appear to be the router. Have you tried resetting it and configuring
from scratch ? Alternatively, have you a different router to try ?

Ive reset it twice.
I reloaded the router os.
I even have two backup routers, one linksys and netgear.
Both are doing the same thing.

I just unplugged my router, waited 30 sec, restarted and
have access.

For now Ive changed the ip to 192.168.3.1

Let's see if this post gets moderated through...

Try putting http:// in front of the IP address.

Opera automatically puts http in front and I cant get though.

I put http:// in front on ff & chrome - same issue.

Ok. I just started FF and I immediately lost access to my router. I cant
access
the router from any browser now. I dont know what in the heck is going on
but this is a serious problem for me.

Evidently *something* is seriously awry with Firefox so the first step
would be to completely remove it using Synaptic Package Manager, this
will also get rid of all configuration files related to Firefox.

After that, reset the IP range again then if you are feeling brave you
can try it put Firefox back and see if the complete removal process
has removed whatever glitch caused this unusual behaviour.

I did uninstall firefox last night. I also deleted the files in home.
My ip now is 192.168.4.1 but I havent tested it out yet.
I'll post back later when I have some time to test it without
being off line for a bit.

After completely uninstalling ff and config files, reinstalling and for
good measure,
switching my ip again, as soon as I started ff, I lost access to my router.

Whatever problem you've hit here is certainly a doozy and not in the
normal scheme of things ! Doesn't make sense in a malware scenario
either so I'd rule that out too. Short of a total clean OS install,
perhaps on other hardware or at least a new HD, or not using Firefox
any more on the current build I'm out of ideas on this one.

This is a brand new install of the OS. Its not even three weeks old.
And the hard drive is brand new. I formatted, slow, myself.

I agree that not using firefox is currently the only solution but, I use
it with my work - tools that Chrome doesnt have so - its a real serious
issue.

At a loss trying to figure out any mechanism whereby Firefox would
blacklist the router IP range, which appears to be what's happening.
Is it possible to go back and use *any* other IP range you set the
router to before ? I.E. is this blacklist being kept somewhere ?

If the list is being stored then the hosts file would be a likely
source so have you investigated that route ? Look in /etc/hosts.deny
too as well as /etc/hosts itself.

There is nothing other than the default marked out language in both
the hosts.deny and hosts files.

Ive been working with sequences of turning on and off things.

Before I left for my soccer games this morning I turned on ff, lost
connection to my router. I left ff on and rebooted my router. When
I got home tonight from the games I noticed chrome and ff both
have access to the router.

So, for now, ff is staying on while I need access to it because
when I turn it off and then on, Ill lose access to my router.

That's even weirder !! The mere opening of Firefox does something that
makes the router lock up but if FF is already open and the router is
re-booted then access comes back. Reading back you've already tried
the obvious which is changing the router but for completeness try
changing the network cable between the Ubuntu system and router. A
very long shot but you've got into that sort of territory now
What you need to look at is what's common to everything you've tried
so far - even using a different network card ( or fitting a card if
using on-board, or a different wireless card if connecting that way ).