Setting up 3CX Failover.

[Comp-Carlos]

Morning Guys,

We wish to set up fail over for our 3CX instance (we'll be using x2 Call4Tel NX96's) and I just want to make sure that we have all of our bases covered. I've read over the guide on how to set this up (3CX Failover), however I have a few questions.

• The documentation mentions that as a prerequisite "Two (2) 3CX PBXs each with its own public IP". I just want to make sure that we in fact require two separate Public IP addresses or whether two separate Private IP addresses are useable and that it's just important that the servers have unique IP addresses. For example, on the LAN the two servers would be 10.0.0.10 and 10.0.0.20. however, the WAN will remain 15.0.0.1. Or do we require two separate internet connections and two Public IPs in order for this to work?
  • We currently have two separate lines coming in and I could configure each box to use a different gateway\update DNS with a different Public IP, but, if possible, I want both instances to use the same Public IP and only update DNS should that line go down and not for it to be dependent on the box.

Should you guys have need any more information, let me know, appreciate any help I can get.

Regards,

Carlos

 

[SteveITS]

No you don't need a second public IP. When the failover happens you can change the NAT forward and the split DNS entry to point to the second server's IP.

Since you're Bronze see this.

 

[Alejandro_3CX]

Hola Carlos,

The official guide mentions two public Ip addresses because it refers to both PBX installed in the cloud, so each one behind a different public IP.

However, if you want to install both PBX in that same LAN behind the same public IP you can do it too, but bear in mind the following:

• Split DNS must be configured
• You will need to use advanced scripts to update the DNS and the local FQDN.
• Local deskphones must be provisioned pointing to the FQDN and not local IP address.

Have a great week ahead!

 

[SweetAction]

In addition to the 3 things that Alejandro_3CX stated, you'll need the NAT rules on your firewall to point to the second IP during a failover event.

Sometimes it's easier to script a re-ip of the second PBX during failover - when we use 3CX's failover function we do a script to:

1. Shut down the switch port the primary is connected to
2. Re-IP and reboot the second PBX to the same LAN IP
3. (depending on specific firewall) kill all open states to the PBX's IP from the firewall.

I'm just going to offer this, take it as you want. In my opinion, It's FAR BETTER to handle failover at the machine level then the 3CX level. Make the 3CX box a Virtual Machine and use your hypervisor's failover functions to handle hardware issues. You skip many issues, including data that's up to a day out of date/missing + easy fail back + way less scripting. Even if the hypervisor is only running the 3CX machine, it's still worth it.

 

[bit101]

Hi,

i have also a question to the HA setup.
Do we have to configure both 3CX nodes manually from hand or does the slave node pull the pbx settings like extensions name, number from the master?

regards,
Norman

 

[SteveITS]

@bit101 Neither, it restores via schedule. See step 2.1: https://www.3cx.com/docs/failover/#h.x7ootglq7juf