I’m having this issue on every cloud platform I use and thought I’d see if anyone had any suggestions. We have settled on using Amazon for this now, but here’s the situation. I have a Balance 305 in our office, 192.168.4.1. I then have FusionHub on AWS in the same subnet/VPC as our 3CX phone system. Both have a 172.31 internal IP address plus an external Elastic IP.
When I create the PepVPN tunnel from our office to FusionHub, we can access 3CX via its local internal IP address as expected. The problem is that all calls have no audio, and I’m told it’s a NAT issue, as 3CX shows my softphone registered from the internal IP address of FusionHub, its 172.31 address.
If however, I configure our 3CX softphones to connect to 3CX’s public IP address, calls work fine with full audio, even if I send all traffic over PepVPN. The difference is that 3CX sees my softphone as registered from 192.168.4.100 being my desktop.
I’ve tried messing with the NAT options and so on but no luck here. If I change routing mode to IP forwarding then 3CX sees my softphone IP as our WAN2 public IP address but still no audio. The only way we were able to make it work in the past when using VMware was by changing the default gateway on 3CX to be FusionHub’s IP address vs the actual Internet Gateway’s IP address. Calls worked fine with that but the firewall checker would always fail.
Would love any feedback as I have this issue even when trying Asterisk. Thanks!
I suspect that your 3CX doesn’t know how to route back to 192.168.4.0 (can you ping the LAN of the Balance 305 from the 3CX?), and that the SpeedFusion Profile on your Fusionhub for your remote site is currently configured as a NAT profile.
You will need to add a static route to the 3CX server for 192.168.4.0/24 with the LAN of the Fusionhub as the next hop. Then uncheck the NAT mode setting in the fusionhub SF profile and everything should come right.
When you say add a static route to the 3CX server, which device am I adding that on? I see Static route under the Balance 305 and also on FusionHub but it asks for IP network and gateway so not sure what I’d put. When I had this on VSphere I was told the same thing, to set a Static Route from 3CX, but there’s no such option on 3CX as it’s a phone system not a router so there was no way to set it there. If it isn’t set in the Balance or FusionHub then that’s not possible.
Also by default NAT mode is unchecked, so my SF profile already has that unchecked. I can try checking it to see if that changes anything, but it’s definitely already off.
Thanks this is Debian 8 so going to have one of my Linux consultants try to set the static routes now to see if that works. I basically pasted exactly what you wrote to them and gave all IP addresses so we will see what happens. Thanks!
