3COM VoIP phone to work remotely using VPN router and PPTP

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dalearyous

[H]ard|Gawd
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Jun 21, 2008
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we are opening a remote office across the country. i bought a VPN router (RB751U-2HnD) and finally have it call configured correctly so any computer attached to it works on our main office network using PPTP VPN. the one issue i am still having is our VoIP phones do not work on the VPN router.

at our main office we are running 3COM NBX V3000 and every VoIP phone is a 3COM phone. we have auto discovery enabled so all you have to do, at the main office, is plug your phone into POE jack and about 15 seconds later it powers up with the user's extension.

remotely, while plugged in, i just get this:
3com.jpg


any idea what i am missing? do i need to set the IP settings for this phone manually?
 
Go Research on how the 3Com autodetection works. Chances are it's a flat network and using broadcast traffic or there's an option being handed out by the DHCP server at your main office specifying the IP of the Phone Server.
 
You should use SSTP or L2TP instead. PPTP is vulnerable. SSTP isn't much different from L2TP but is more secure.
 
/usr/home said:
You should use SSTP or L2TP instead. PPTP is vulnerable. SSTP isn't much different from L2TP but is more secure.
Click to expand...

doesn't seem like that while solve my phone problem though.

Nate7311 said:
Go Research on how the 3Com autodetection works. Chances are it's a flat network and using broadcast traffic or there's an option being handed out by the DHCP server at your main office specifying the IP of the Phone Server.
Click to expand...

only thing DHCP server shows is an IP address reservation for the 3COM NBX. i read a bit about auto discovery and it uses IP on the fly so the phones i don't think get an actual IP address?
 
usr/home's comment won't have a direct bearing on your operational issue, but may head off a potential security issue in the future.
 
It likely isn't finding the phone system server, because it is on a different subnet. Not sure how the 3com system works specifically, but there should be some way to setup a dhcp option for the remote office which will tell the phone how to find the server.
 
dave99 said:
It likely isn't finding the phone system server, because it is on a different subnet. Not sure how the 3com system works specifically, but there should be some way to setup a dhcp option for the remote office which will tell the phone how to find the server.
Click to expand...

yeah that sounds like it could be it. just no idea how to tackle this. nothing inside the interface of the VPN router seems like it would help.
 
Who installed it for you at the main office?
Do you have any documentation either by the installer or original 3Com?
Do you have support w/ 3Com on the unit? If so, have you contacted them?
Have you googled it yet?
 
local contractor
no
no but i put a ticket in with local company that set it up
been googling for a while now. i do that before i post here.
 
dalearyous said:
yeah that sounds like it could be it. just no idea how to tackle this. nothing inside the interface of the VPN router seems like it would help.
Click to expand...

Does the router in the remote office provide DHCP to the various client devices (pc's, phones etc), or is there a server for that office?
 
the router does DHCP.

in the 3COM NBX manual, there are instructions for setting up a remote phone. basically you configure the phone through its built in menu for: a static IP address for its local network, NCP IP address (phone server) it states it must have public ip address unless we are using VPN which we are so we good there, subnet mask, and default gateway. all pretty normal stuff. then it states to port forward the UDP port range 2093-2096.

i did all this and no dice :(
 
You shouldn't have to deal with ports, since everything is going over the vpn (unless you configured it to only allow specific connections). You gave the phone a proper IP address & gateway in the remote subnet, and the internal IP address for the NCP server? (which should be a different subnet from the remote office)
 
dave99 said:
You shouldn't have to deal with ports, since everything is going over the vpn (unless you configured it to only allow specific connections). You gave the phone a proper IP address & gateway in the remote subnet, and the internal IP address for the NCP server? (which should be a different subnet from the remote office)
Click to expand...

oh, no VPN should be wide open.

yes.

IP: 192.168.88.111
Subnet: 255.255.255.0
Gateway: 192.168.88.1 (IP of VPN router)
NCP IP: 192.168.2.100

(a computer connected to the VPN router can ping 192.168.2.100 just fine ... if that helps)

*edit*
ah! wait a minute
3com2.PNG


something is working because the system sees the phone and states it is an unknown IP address.
(2.65 is the VPN router on the local network)
 
Last edited:
looks like the 3com system isn't allowing phones to join that are out of subnet

any way to add 192.168.88.0/24 to the list of allowed devices?
 
3comIP1.PNG

3comIP2.PNG


you would think i could here but when i hit add and type in any combination of ranges it says it already exists.
 
NBX Manual said:
Network Protocol The transport mechanism for voice packets.
Ethernet only: All communications are at the Ethernet frame layer.
Standard IP: IP communications are used for traffic between NBX addresses. Note: Every device needs an IP address.
IP-on-the-fly: An implementation of IP communications in which devices on the same subnet as the call processor communicate using Ethernet frames; they receive IP configuration settings only when necessary, to communicate with an IP device on some other subnet.
Click to expand...

Try setting the config of that Phone to "Standard IP" and reboot the phone.
 
i don't want to do that though. that would throw every phone off. all our current phones run on layer 2 and therefore do not need an IP.

the remote phone will obviously run on layer 3. i found and fixed a couple settings that would have kept the phone from being able to make outbound calls but there is still no reason why i am getting this.
 
Do you have Licensing for true IP Communications? Another note found in the Manual. I'm assuming that true IP-based communications require a separate license. Do you have this?

Note: IP communications are optional features of the NBX 100 which require separate licensing.
 
i talked to the company that setup the phone system. they are stumped. not a licensing issue.

this is where i am at now:
1.PNG



2.PNG



3.PNG


if i hit reset device, it will reset the phone. so they are communicating, in a way.
 
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