RT-AC66U B1 Media Bridge DHCP bug remains

[vibroverbus]

Today is 'obsolete router notes' day for me this is the first one. This is an "FYI uninteresting for .01% of the population" for this old gear, but I had trouble determining what the current situation was for some of this old junk so I am posting for the benefit of others stuck in "have to repurpose some old stuff for some reason" mode. This post is just an update confirming known issues with perhaps a few additional notes.

Becausereasons I had to go into the caverns and dig through the archives to grab an old ASUS router to use as a wireless-to-ethernet bridge this weekend. After trying another router which was soft bricked (subject for next post) I moved on to a RT-AC66U B1 that was like new and had never been in service for long, assuming this would be super easy. Was not really.

Cut to the chase:

• This model (presumably including RT-AC68U as they are same firmware) has bug(s?) with DHCP when put into Media Bridge mode. This has been reported years ago.
• The current (possibly 'final'?) version of firmware for these 3.0.0.4.386_52062 and it still has this problem which is the point of this post
• Most of the Media Bridge setup seems to work - unit will connect to Wifi, and will nominally bridge ethernet clients. Unit boots up with 192.168.50.1 for a moment, before it starts to sort out its LAN address.
• But from monitoring the network DHCP server and looking at the ASUS MB - it seems like the router then will pick its own IP address. The DHCP server does not see a request and issue a lease. The MB appears to do something like this... First look for an existing client IP address i.e. "192.168.1.123" (possibly it looks for the highest IP that is active?) and then seems to give itself the next sequential number - 192.168.1.124. The router will not appear in the lease table for the networks DHCP server. I've tested and confirmed this several times, if you change the DHCP settings and therefore force it to reset, it will pick the next IP address i.e. 192.168.1.125, again not appearing anywhere in the real DHCP lease tables.
• Once router has apparently picked itself an address, since you can't see it in the host DHCP server, you have to use some other means to find it if you want to reconnect with it... For this ASUS Discovery Tool does work to find it after that and router responds properly to the web GUI.
• It seems possible that the router is also still trying to run its own DHCP server, this has been reported as a significant problem also. When going to the 'hidden' DHCP page, it does show DHCP 'on' by default. I did not connect via SSH or anything to try to see what processes are running or look at config files under the hood or any of that business to confirm as I just wanted to move on with the project.
• Running MB mode with another ASUS-obsolete-router results instead in "expected behavior" i.e. router appears at DHCP server host, lease is very visible and correct, etc.

Its entirely possible this is fixable by loading Merlin and using standard Merlin techniques to modify config files etc., bit in the end I un-bricked the other router and then it went much smoother, so I am using that instead. Again just FYI in case 1 person tries to get this working with old gear.

 

[ColinTaylor]

Can you remove the white/grey colour attributes from your text as it makes it nearly invisible when viewed with certain themes. Thanks.

 

[vibroverbus]

Can you remove the white/grey colour attributes from your text as it makes it nearly invisible when viewed with certain themes. Thanks.

On this thread also? I used no color at all on this one. The only text formatting I used was italics.

OK weird. Yeah there's embedded color tags in there in weird spots. I did NOT put those in. Maybe editor put those in from a cut & paste? But I've never picked white or gray as a color so very strange.

 

[ColinTaylor]

On this thread also? I used no color at all on this one. The only text formatting I used was italics.

 

[vibroverbus]

View attachment 70989

Should be fixed. Mystery, but, fixed

 

[ColinTaylor]

Yeah, I've seen this before in other posts. Looks like the editor inserts them without people knowing.

 

[wouterv]

I cannot make up what the issue is, too much text, too much description.
For many years I had a RT-N66U, succeeded by a RT-AC1900U as Media Bridge attached to a RT-AC68U Router without major issues.
The RT-AC68U, RT-AC1900U and the RT-AC66U_B1 are technically quite the same, with equal firmware.
The setup I used was straight forward as follows:

In the Router:
Given the the Router has the default IP address 192.168.1.1
LAN > DHCP Server > IP Pool Starting Address = 192.168.1.3

In the Media Bridge:
IP Address: give the Media Bridge fixed IP address = 192.168.1.2
Subnet Mask: 255.255.255.0
Default Gateway: Router IP address = 192.168.1.1
DNS Server1: Router IP address = 192.168.1.1

 

[vibroverbus]

I cannot make up what the issue is, too much text, too much description.
For many years I had a RT-N66U, succeeded by a RT-AC1900U as Media Bridge attached to a RT-AC68U Router without major issues.
The RT-AC68U, RT-AC1900U and the RT-AC66U_B1 are technically quite the same, with equal firmware.
The setup I used was straight forward as follows:

In the Router:
Given the the Router has the default IP address 192.168.1.1
LAN > DHCP Server > IP Pool Starting Address = 192.168.1.3

In the Media Bridge:
IP Address: give the Media Bridge fixed IP address = 192.168.1.2
Subnet Mask: 255.255.255.0
Default Gateway: Router IP address = 192.168.1.1
DNS Server1: Router IP address = 192.168.1.1

Oh man. If you can’t be bothered to read the actual post then don’t bother replying. Just ignore it if you’re too lazy or not intelligent enough to be able to read several paragraphs of text. It makes no sense to pretend to give an answer to something when you haven’t even read the details.

 

[wouterv]

I am convinced my answer covers your troubles and will solve the issues your describing.
Media Bridge is a rather solid solution for its purpose, specially when you use it in the way I described.

 

[vibroverbus]

I am convinced my answer covers your troubles and will solve the issues your describing.
Media Bridge is a rather solid solution for its purpose, specially when you use it in the way I described.

Well. If you weren't so lazy you would've read that I've solved my problem and guess what it DOES involve using ASUS media bridge, just on another model, and this purpose of this thread is only to give people with this specific hardwarea heads up, Since this definite hardware specific bug wasted a bunch of my time and I wouldn't want somebody else to get dragged into it. like your cute little suggestion to change the IP address on the unit I talk all about that. and why that isn't quite so easy as it normally should be because this bug does some weird thing with picking IP addresses so you need to use router discovery tool.

yes the media bridge mode on my other routers working awesome thank you very much.

 

[wouterv]

like your cute little suggestion to change the IP address on the unit I talk all about that.

During first setup of the Media Bridge you have to decide Automatic IP or Manual IP.
And of course, if you first choice is Automatic IP, you have a hard time to find what IP address was given by the Router DHCP Server.
This was my last about this crazy topic, good luck.