pppoe on Debian running 3cx

[SandroD]

I wonder if anyone on this forum can help

I have an install of 3cx on linux, all seems to be working very well until I decide to stand up the PPOe interface.


as soon as i do it, there are several services that simply stop. i believe they all rely on the loop back interface but i am looking for your confirmation. These are the services that fall off :

3CX PhoneSystem 01 IVR Server
3CX PhoneSystem 01 SIP Server
3CX PhoneSystem 01 Queue Manager Server

routing appears to be correct, once ppp0 is up it becomes the default routing. the OS is communicating to the internet just fine and the loop back interface is pingable on the standard 127

if anyone has any ideas i can start posting some of the configuration bits and pieces which i am pretty sure you will find very standard.

 

[StefanW]

no, no other interface then the eth (ens) should be present on the host.
ppoe should be done by your routing gateway.

 

[SandroD]

thanks. that's too bad but i can get around it.

the reason for the ppp interface is that the router is already mapping out ports for voip to another server therefore i was trying to obtain a public address on the same VM where 3cx is running.

 

[Elliot Cater]

If you have been assigned a subnet with multiple Public IP's from your ISP and your router can handle virtual IP's (proxy ARP, IP Alias, CARP etc...) you should get your router to do 1:1 nat for your public IP to a LAN IP. Then just assign 3cx VM the LAN IP?

Is it that you have only one static public IP to play with?

 

[SandroD]

sort of.

basically this is what happened. my ISP provides with a modem but several ports for VOIP, 5060 and other RTPs are mapped out already for a VOIP service that they provide, which of course i don't use.

turns out that the router is programmed by the ISP to function in routed+bridge mode. this means that you can use it as router and at the same time you can have 1 or more of the end points to initiate a PPOE authentication. as result of that you can have as many public IP as you want ( all dynamic )

because of that I had to come up with ways to obtain a public IP address on the 3CX server itself, so i have originally thought at using PPP right at the OS level but clearly that did not work because 3CX doesn't handle well multiple interfaces. I still think that it was getting somehow confused with the loopback interface but I wouldn't go too deep into that.

finally i came up with another solution, I have a 2nd router cascaded that authenticates over PPOE and once obtained the public IP that is then I have mapped all the required ports to the 3CX server.

ISP router >> 2ndRouter (PPOE) >>NAT>> 3CX server

it all worked out in the end.

 

[Elliot Cater]

Glad you got it working but remember - adding extra devices adds an extra point of failure.

I'd also be very wary of using the ISP's dynamically assigned IP, especially if they're liable to change and leave you without inbound calls. I suppose though it depends wether your SIP trunk provider needs an IP address or can resolve from DNS (so you could get a dynamic dns account? I'm no SIP expert).

Debian itself will do PPPOE no problem at all, with just a couple of extra packages from the repo - see this guide looks super easy and persistent:

https://blog.confirm.ch/using-pppoe-on-linux/

Then just ditch the default gateway on your LAN's nic. You'll still be able to get the 3cx box from a LAN subnet if you need to manage it locally etc.