Can't get to the router web interface from one PC

[fromaron]

I have a strange problem for few months already and wonder if anyone experienced something similar or knows the solution.
The problem is I cannot access my router from one PC only. When I try it gives me wrong password (see attached screenshot) problem even though I didn't get to the login page.
From all other PCs it works like it should. After typing the router IP address in the browser it comes up with login page.
It's almost like when I try it from my PC it sends login information or clicks Ok without me seeing the page.
I tried already all the common staff like disabling AV, firewall, clearing browser history, cache, cockies, different browser etc.
The ipconfig shows all the correct settings etc, just no connection to the router web interface.
Should I mention the internet works just fine and my PC registers on my local network and happily communicates to other PCs.
Any suggestions?

[kevin1341]

Hi, Have you tried cleaning the browser cache?

[autotuner]

Its a Windows machine?
If so...have you deleted the stored passwords under User Accounts?

[fromaron]

Yes, the browser cache was deleted.

autotuner, I have only stored passwords for other computers as well as to my home server stored in windows vault. Nothing there is for the router. I have them all listed separately, so I can manage them individually. Also I never had the router save password activated. I remember from my old routers if I tick save password option I still presented with the login page and password pre-filled. This time I don't have a chance to interfere.

[autotuner]

Ok, strange one...
Try to prove if its the router or the PC.
Start with a new IP address for the PC, give it a static.

[Philquad]

did you try changing the router password from another pc
then try to login
if not, just format the ####er, sorry

[fromaron]

Ok, strange one...
Start with a new IP address for the PC, give it a static.

I always use static and yes, tried with dynamic IP (got different IP) - no luck.

did you try changing the router password from another pc
then try to login
if not, just format the ####er, sorry

I hear you... That is what comes to my mind as well. But I am reluctant to go this way as this is the only thing that doesn't work.

[autotuner]

Gotta love this stufF..
Sniff the session to see what is going on with whom? Although it may be a https session...saying that, enable http and try again.
Search the registry and all files for anything stored with the router IP address referenced ?

[fromaron]

I think that will be interesting. Will try next time when I have a bit of spare time. Will use something like wireshark from two PCs and compare logs.
There should be something different in there.
I even have a conspiracy theory (some kind of worm trying to get to my router behind the scene...)

[lsemmens]

Try an ipconfig /release all followed by a ipconfig /renew from the affected PC. These weird ones are often the hardest to track, and the simplest to fix....when you know what it is. Out of curiosity, what sort of router?

[best4less]

Silly question but did you try a different browser like Firefox or Google Chrome etc ...

[fromaron]

Try an ipconfig /release all followed by a ipconfig /renew from the affected PC. These weird ones are often the hardest to track, and the simplest to fix....when you know what it is. Out of curiosity, what sort of router?

I tried it and get

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\Dad>ipconfig /release

Windows IP Configuration

The operation failed as no adapter is in the state permissible for
this operation.

C:\Users\Dad>ipconfig /renew

Windows IP Configuration

The operation failed as no adapter is in the state permissible for
this operation.

C:\Users\Dad>

I guess due to the static IP I am using.
My router is TP-Link 4300 (750N).

Silly question but did you try a different browser like Firefox or Google Chrome etc ...

That was the first thing I tried.
Something to do with my PC in general, not the browser I am using.
This small annoyance does my head, LOL.

[fromaron]

Just ran wire shark with filter.
My PC IP is 192.168.1.2 and the router is at 192.168.1.1
There is one checksum error (see the screenshot).
I am not sure what does it mean and how to fix it. I will appreciate any help or explanations on the error I captured.



It says the error maybe caused by 'IP checksum offload' whatever it means.

[allover]

Have one of those, got locked out over the week end and ended up resetting it and going back in with admin/admin
Check your updates as there are recent ones available, go to them via settings in the router

[autotuner]

Do you get the same error every time you try?
A single checksum is nothing to worry about, just means that the payload checksum and the calculated checksum do not match, lots of them or reproduceable ones are a concern.
You didn't see any authentication being passed?

[fromaron]

Have one of those, got locked out over the week end and ended up resetting it and going back in with admin/admin

Resetting it doesn't help and I have the latest firmware installed yesterday.

Do you get the same error every time you try?
A single checksum is nothing to worry about, just means that the payload checksum and the calculated checksum do not match, lots of them or reproduceable ones are a concern.
You didn't see any authentication being passed?

I actually found the checksum offload captured by wireshark is mainly a cosmetic problem. Apparently NIC can offload the checksum calculation and wireshark doesn't capture the offloaded one, hence the error. If I had the packet repeated then it would mean a problem.
So I simply disabled the IP checksum offload in the NIC parameters and recaptured it - no more errors of the type.
As far as authentication goes, I don't see any password or username coming from my PC to the router. Just standard query with immediate reply from the router that authentication failed.

[autotuner]

Hmm, so if the PC is not sending any authentication, then the router must have cached the session somehow. If there is no way to clear the HTTP server in it, then my next step would be a firmware upgrade, or at least a firmware reload.
Can you run Tomato or DD-WRT on it?

[fromaron]

That is the most incredible thing.
I recently upgraded firmware (had problem before that as well) and the router was reset to factory default.
If it was the router issue I wouldn't be able to access it from other PCs I have.
There is something wrong with my PC somewhere, I don't know where to look now.

[allover]

Have you some thing like Keepass, or remembered in Firefox redirecting you, gather you can ping from affected machine. Have you run crapcleaner, small things but worth a try

[autotuner]

Well that is getting beyond fun.
Perhaps there is something in the router logs to give some info, can you enable access control logging, or maximum log level to see if it has a clue.
If a sniff did not show the PC passing any login details, I don't know why the router would throw the error.