ASUS RT-AC68U Proxy Question

[J.T.]

Hi, I have a strange problem and was wondering the cause...

My router is the ASUS RT-AC68U. For the heck of it, I ran the network troubleshooter in Windows 10. When I do that, I get an error of "Windows could not automatically detect this network's proxy settings."

However, the internet and intranet work fine.

I have no proxy set up. This error does not happen when I run the troubleshooter on my other Windows 7 machines. Also, when I tried another router, the Windows 10 box didn't give the error. My question is why is the problem only with Windows 10 + the ASUS RT-AC68U.

PS, when i uncheck the automatically detect proxy setting in Windows 10, the problem is gone. WHY?

 

[ColinTaylor]

The message refers to Web Proxy Auto-Discovery (WPAD). The router's DHCP server issues a 252 option which would normally contain the location of a PAC (Proxy Auto-Config) file. However, I think on the Asus this string is a null value. So I guess that Windows 10 is just a bit more verbose about what it perceives as an invalid response from the router.

 

[J.T.]

Interesting! So everyone with a Win 10 box and this router will have this error when the troubleshooter is run?

Would Merlin's firmware fix?

 

[ColinTaylor]

Would Merlin's firmware fix?

Sorry, I don't know. I remember there were various changes made regarding option 252 in Merlin's firmware but I don't remember the specifics, or whether they also applied to stock firmware.

 

[ColinTaylor]

I've just done a little test on my router (running John's fork of Merlin).

With the following line in dnsmasq.conf (the default setting) the proxy error message appears.

dhcp-option=252,"\n"

Removing that line (and restarting dnsmasq/reinitialising the client's network adapter) makes the error message go away.

I don't have a router running stock firmware but I'd assume the same line is in there as well.

There were discussions about this option in the past because of issues with Windows 7:

https://www.snbforums.com/threads/tell-clients-to-stop-asking-for-proxy-settings.12226/
https://www.snbforums.com/threads/dhcp-flooding-my-router.11896/
https://www.snbforums.com/threads/recent-error-log-issues.18748/#post-133522
https://social.technet.microsoft.co...scovery-protocol-wpad?forum=w7itpronetworking

I suppose it's possible (likely?) that non-Asus routers don't use option 252 and therefore it wouldn't be an issue for Windows 10.

 

[john9527]

PS, when i uncheck the automatically detect proxy setting in Windows 10, the problem is gone. WHY?

Because windows proxy detection is 'not consistent', putting it nicely. The first thing I do on any install is uncheck that setting.

@ColinTaylor - If you delete that line in dnsmasq, I'll bet the windows event viewer will show a lot of WPAD warnings.

 

[ColinTaylor]

@ColinTaylor - If you delete that line in dnsmasq, I'll bet the windows event viewer will show a lot of WPAD warnings.

Hmm, I'm sure you're right but I'm not seeing anything at the moment. Been trying with Windows 7, 8.1 and 10 but haven't seen anything yet. But then again I'm not seeing the repeating Windows 7/DHCP messages in the router syslog either.

 

[J.T.]

Thank you for the feedback!

Can you post a link that illustrates how I change that line so I can test?

 

[ColinTaylor]

Can you post a link that illustrates how I change that line so I can test?

To use custom scripts or configs you need to be running a 3rd party firmware like Merlin. However, assuming your Linux skills are up to it, you can make the following temporary change in stock firmware.

1. Log onto the router with SSH or Telnet.
2. Edit /tmp/etc/dnsmasq.conf
3. Remove the line that says dhcp-option=252,"\n"
4. Save the edited file
5. killall dnsmasq
6. dnsmasq --log-async

 

[Johan N]

Hello,

Greetings from Holland.
I have got exact the same problem, tried everything till i found this article.
Does anyone knows if there comes a solution for this problem (maybe a update for the router?)

I hope that there will be a solution for this problem.

 

[RMerlin]

A solution to what problem? There is no proxy server on the router, so this is perfectly normal. Disable automatic proxy detection. This parameter is old legacy stuff that was only used within corporate networks.