ASUS RT-AC66R Firmware Version 3.0.0.4.374.726 "DUAL WAN"

[RaptorWatcher]

Anyone try this feature?
I have a few observations

I have it set up...
1. Does fail over from Cable on WAN to DSL on Lan1 port.
When primary WAN comes back on line it appears to stay on fail over... i.e. does not check primary. no way so far to address this that I can see.

2. Traffic monitor is not accurate... upgraded from 3.0.0.4.270 where this feature worked.

continuing to tinker with this... any other experience is appreciated

Just noticed that tag is incorrect for model RT-AC66R should read RT-AC66U

 

[RMerlin]

Failure to switch back to primary LAN once it recovers is a known limitation of the current Dual WAN implementation.

 

[RaptorWatcher]

Thanks.. I also note that the traffic monitor was also noted to be inaccurate by others. Any insight to this?

 

[SoCalReviews]

Failure to switch back to primary LAN once it recovers is a known limitation of the current Dual WAN implementation.

I noticed the same issue with the RT-N66U and it's recent firmware. I hope Asus is able to implement a "switch back to main primary WAN when working" feature in a future firmware release. Being able to customize the length of time in minutes, hours and days before switching back to the main primary WAN when it's restored would also be a convenient feature to have.

 

[Brazilian Joe]

If you unplug the secondary WAN it goes back to the primary.
At least it did in the previous versions.

I have tried load balancing, and that seems to be more problematic.

I could only browse the internet for a few minutes, and it would fail intermittently.

It also does not accept routes.

If I add a route to reach a specific IP through one of the WANs, it shows on the interface but does not apply. Also setting a intranet computer IP address to go trough a specific WAN does not work.

It is a real problem because some ISPs not only block DNS queries to other DNS servers, but also only accept DNS queries if it originates on one of their IP address allotment.

The Dual WAN config does not seem to stick explicit routes for each DNS address to use the right WANs, so it breaks.

I also tried setting separate subnets on each WAN for the exercise. On the Primary WAN I have set up a 192.168.10.0/24 network, and on the Secondary WAN a 192.168.20.0/24 network.

My connections seemed to consistently prefer going through the secondary WAN, and I could never, ever reach the modem address at the Primary WAN.

Tried digging at SSH, but simply adding routes didn't do the trick. Firewall changes might be necessary, there might be some NAT/mangling going on which is breaking it.

 

[Brazilian Joe]

Let me describe my test scenario a little better:

Modem 1 (Primary WAN):
IP: 192.168.10.1
Subnet 192.168.10.0/24
ISP: GVT
DNS 1: 200.175.89.139
DNS 2: 200.175.182.139

Modem 2 (Secondary WAN):
IP: 192.168.20.1
Subnet 192.168.20.0/24
ISP: NET
DNS 3: 201.21.192.162
DNS 4: 201.21.192.167

ASUS RT-AC66R
Primary WAN: WAN
Static IP
IP: 192.168.10.20
Gateway: 192.168.10.1
DNS: per Modem 1

Secondary WAN: Lan Port 1
Static IP
IP: 192.168.20.20
Gateway: 192.168.20.1
DNS: per Modem 2

And the problems in my previous post happened.

I have enabled 'Routing Rules' in the Dual WAN conifguration page, but it seems that part of the configuration page is a dud, the settigns are never applied.

I checked the routing table using SSH and never saw my rules there.

Manually adding them did not improve matters.

 

[PrivateJoker]

@Brazillian Joe - thank you very much for sharing your extensive notes on the configuration of and operation of the dual WAN. It seems to be a feature that a lot of people have an interest in but certainly still far from a mature, stable feature on most consumer gear (with the exception @Stevech has mentioned elsewhere of certain Cradlepoint gear that is really built on cellular WAN as a selling point).

If you unplug the secondary WAN it goes back to the primary.
At least it did in the previous versions.

What if instead of unplugging one of the WAN connections they just go unresponsive/dark, will it still switch over without being physically unplugged?

 

[Brazilian Joe]

I was thinking 'what if load balancing also had failover intelligence?'

Then my tests stumbled in this problem, and routes initially seem to defeat the intent of baking failover in load balancing.

Perhaps marking packets with different categories:

(no mark: use default load balancing rules)
1) Always use WAN 1 no matter what (for DNS and servers)
2) Always use WAN 2 no matter what (for DNS and servers)
3) Prefer WAN 1, use WAN 2 if not available
4) Prefer WAN 2, use WAN 1 if not available

These marks would be added according to rules set by the Dual WAN routing table, and be used later on to select the appropriate destination for each packet.

I don't know how to make load balancing by hand, don't know if it would need additional bridges for each of the 4 categoeirs or even if the marks are necessary. Maybe I am barking at the totally wrong tree. But I thought it would be nice to share.