Dual WAN Problem

[NFSbuff]

Hi all. I'm experiencing a very strange issue that I can't seem to solve. The setup in question is attached to this post. Now to the problem.

Currently, I am given two dynamic IP addresses from my ISP. The DrayTek router shown has two WAN ports. Accessing the modem's configuration page shows the 2 MAC addresses of the router registered. Now, when I initially plug everything into the switch as shown in the image, only one WAN port picks up an IP address. If I unplug the dead WAN part on the router and plug it back in, it picks up the second IP address and the world is a better place. ...for about 6 hours, at which point the same WAN port dies again saying it is disconnected.

What is the issue here? My ISP says they can see the MAC's of both WAN ports on the router (when its working), and when it works, its fine. DrayTek support is no help, saying they've never seen this before and have no idea where to even start. Why is one WAN port suddenly becoming "disconnected" when nothing changes? This includes no changes on the LAN side either.

I welcome any ideas here.

 

[thiggins]

How are you trying to use the two IPs and how do you have the router WAN ports configured?

Multi WAN port routers are more suited to using two Internet services, not multiple IPs from the same service.

If you are just trying to use assign the two WAN IPs to LAN segments, you don't need a multi-WAN router. You just need a router capable of one-to-one NAT. Check the Draytek documentation.

 

[NFSbuff]

Thanks for the reply.

The two IP's are used for two servers that both require port 443 and 80 traffic, coming from two different domain names. The router is setup so that servers A and B are fixed to WAN ports A and B, respectively. From the outside, traffic from domain 1 comes through WAN A and traffic from domain 2 comes through WAN B. For clarification, these domains are DynDNS domains, which the router allows to be directed to and from a specific WAN port.

Like so:

Server 1 <-> WAN 1 <-> Domain Name 1; 443, 80 traffic
Server 2 <-> WAN 2 <-> Domain Name 2; 443, 80 traffic

 

[thiggins]

I suspect it could be the switch. You don't really have two WAN connections and splitting one with the switch could be messing up the ARP tables somewhere.

Again, this can be (better?) done with a router handling one-to-one NAT.

 

[NFSbuff]

The one-to-one NAT option would be the ideal solution, but I'm using 2 dynamic IP's so I'd run the risk of having a server become unavailable if an IP were to change.

Checking the ARP table in the router, I noticed some anomalies that point to an ARP table somewhere as the cause of the problem (although I can't confirm that yet). The router gives me the option to establish WAN connectivity via ping instead of ARP, so I'm going to try that.

 

[thiggins]

Sorry, I missed the dynamic IP issue. Do you have a dynamic DNS client for each WAN port?

 

[teknojnky]

normally when given 2 (or more) ips, they are static, meaning they don't change.

are sure they are dynamic? they both change every time you connect?

even if they are dynamic, they should normally be sequential order

this really should be done with IP mapping/one to one mapping, but I see the problem with using dyndns which generally only handles one ip/client.

 

[NFSbuff]

@Tim: Yes, this DrayTek allows for 3 dynamic DNS clients, and each one can be mapped to listen on a specific WAN port or a preferred order of ports.

@teknojnky: Yes, both IP's are dynamic, as specified by both my ISP over the phone and as stated on my bill. Plus, both WAN's connect as DHCP clients. Strangely, the IP's are not sequential. One starts in the 60's, and the other in the 70's. My ISP appears to have long lease times on the IP's, because they change maybe 3-4 times per year, even though I'm in a heavily populated area.

So being able to get back to the physical router and do my unplugging and replugging routine again, I'm now trying something different. The router has an option for each WAN port called "WAN Connection Detection" with two modes: ARP Detect and Ping Detect. The default setting is ARP Detect. I'm changing both to Ping Detect, and hitting a site outside my ISP, like Google.com. We'll see if this works. So far, 6 hours in and nothings died as before, maybe this will do it.