vibroverbus
Regular Contributor
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:
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.
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