AC88U - issues with media bridge

[Vic666]

I recently bought 2 AC88U routers - and I already regret it. Yes, the higher speeds are really nice but the firmware is just one huge mess.

What I'm trying to achieve seems easy enough: I have one router serving the internet (192.168.0.1), and one router configured as media bridge (192.168.0.177). The two are connected via WiFi with each other, of course.

I have a few devices connected to the media bridge via ethernet, one of them being a Linux workstation with KVM installed on it and several VMs (dynamic ip, in bridged mode).

Even though the workstation and each VM have their separate MAC addresses, the DHCP server seems to give out only one IP address to the whole machine, on a first come, first serve basis.

It gets even worse. So I tried to set static IPs for the remaining machines, just to get the network running while I'm waiting for a better solution with regards to DHCP. Unfortunately, that didn't have the expected effect, I can't get past the media bridge. Meaning I can ping the media bridge but I cannot ping the internet router. But the media bridge can ping the internet router just fine. WTF? What is blocking here, and why?

I never buy a product right after it comes out simply because I don't want to deal with these kind of kinks. That's why I'm really surprised no one ran into these same issues before me.

Anyway, do you have any advice for me how to deal with this situation short from returning the routers and buying others? Would switching to Merlin help me in this case?

 

[JDB]

Sounds like you have issues with your VM setup and IP assignment, not media bridge issues.

Can you temporarily plug the host server directly into the router and test all you want to work does there before you include the media bridge?


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[Vic666]

Sounds like you have issues with your VM setup and IP assignment, not media bridge issues.

Can you temporarily plug the host server directly into the router and test all you want to work does there before you include the media bridge?

Thanks for taking an interest.

I'm not a network engineer but I'm not new to this, either. This same setup used to work for 3 years now, all I did was to exchange the router and media bridge for two Asus AC88U (I was working with Mikrotik devices before).

But for no one having to rely on my own judgement, I removed the server from media bridge and attached it to the router directly as requested. Then, it all just works the way it should. I guess this confirms that the issue is not with VM setup and IP assignment.

 

[JDB]

Interesting.

There are some issues I know of around Broadcast messages (as DHCP/ARP require) and media bridge mode, however these seem to manifest themselves as occasional blips in service rather than just not working as you report.

If you have a search for ‘media bridge’ you’ll find a few threads talking about what I mentioned but I’ve never seen anyone saying the same as you.

Sorry I can’t offer any other ideas!


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[Vic666]

So, here's an update on the situation.

Attached to the router, I have a Synology NAS. Since it has a built-in DHCP server, I enabled it and then disabled the DHCP server of the Asus router altogether.

I'm happy to report that DHCP works now, even across the media bridge, on all machines.

In conclusion, the DHCP implementation of the AC88U is an embarrassment. Am I right to assume that Merlin would not have the same issue?

 

[JDB]

I still think you’re jumping to conclusions. DHCP works just fine, not a common reported issue.


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[Vic666]

I still think you’re jumping to conclusions. DHCP works just fine, not a common reported issue.

You may be right but what other conclusion could I draw based on these findings?

My setup is really quite simple. Network is a 192.168.0.0/24, no other subnets i.e. no routing, no VLANs, about 20 devices in total. With exception of a few devices (NAS, printer, server), all others have a dynamic IP.

Attached to the media bridge, via ethernet, I have one workstation with KVM and one server with Linux containers. Both VMs and containers are getting dynamic IPs through bridging of the physical ethernet adapter.

As we could see before, address retrieval and routing works just fine when attached to the router directly. When attached to the media bridge, however, only one IP would work per physical machine. And I mean that literally, DHCP would serve one address and any other address on the same machine (i.e. static address or an earlier DHCP lease) would not be routed past the media bridge, neither to nor from.

These issues simply disappear when changing the DHCP server to Synology.

 

[kfp]

These issues simply disappear when changing the DHCP server to Synology.

Which DHCP server does the Synology use? ISC?