Hi Folks,
I do have a DUAL-WAN setup, with failover working fine for "normal" clients, wanting to reach out to the internet.
However, I added some additional "Phone lines" via an external SIP-Provider.
For this purpose, I deployed a small, embedded hybrid PBX (one landline + VOIP/SIP connections).
Now, when there is a failover of my WAN, the PBX will not follow, meaning it will not (re-)register with the external, cloud based SIP-Provider.
My understanding is, that this is a flaw in the way SIP is designed so basically, this "works as designed" or better a well known challenge.
This is how my setup looks like:
My question is, if there are any ways to "solve" that problem?!?!
I noticed, that my PBX, when I do a restart, it will - of course - re-register fine via the active WAN, no matter which WAN is the default at that time.
Also, when I toggle its ethernet port on my RB4011 it will refresh its DHCP lease with the DHCP-Server (the PBX is a non-PoE unit, but still) and also perform a re-registration!
So, any hints on a script that can toggle (10secs downtime / flap) that ethernet port the PBX is connected to, when a WAN failover occurs? Or is there a smarter solution?
Note: WAN-Failover is very simple atm, as the default route to WAN1 is dynamic (via DHCP) and the one for WAN2 is static, with a higher distance...so no scripting foo involved, yet.
Edit: did some more tests and noticed, that when WAN1 comes back, the PBX will not re-register, but stays on the connection via WAN2 and then fails after some time.
I think one has to delete all existing connections in the RB4011 for that unit between toggling the eth10-port or even better, hand out a new IP to the PBX (i.e move it into a seperate VLAN).