Setup adventure with latest install (dnsmasq, default gateways, dhcp, etc.)

I just finished standing up a new PBX box - Asterisk 16/FreePBX 14 with Sysadmin Pro. I ran into a strange network problem, that I fixed, but I thought I’d mention in case it comes up again.

Network config: the hardware PBX lives with eth0 on the outside of the network ( The firewall and VPN gateway lives on The default gateway for both machines is Both boxes also have “interior” Ethernet interfaces ( and I also use VOIP Innovations (with IP Authentication) as my ITSP.

I used the Network Setup feature for eth0 and eth1 from SysAdmin pro and set the default gateway for Eth0 to and the default gateway for the interior network for eth1 default gateway to That was a mistake, and I didn’t catch it until last night. With both default gateways filled in, the system used the NAT gateway to send traffic out from the phone server. This put the outgoing traffic on the wrong gateway device (104 instead of 106) and locked out outgoing calling. It also manifested as a weird “rug pulling” situation where I reset the network and couldn’t get back in because of the open-jawed route, so I had to go to the server to fix it.

So, issue 1 - do not set more than 1 Default Gateway. Perhaps Sysadmin Pro could check for that and prevent bad data, or at least verify the actual setting.

Got that all fixed. Inbound and outbound calling working. Next was getting the DHCP server set up.

The phones use the LAN for all of their communication. They talk to the phone server (on through Option 66. When I set up DHCP, the phones knew how to get to that server (it’s in the local network) but none of the computers could communicate outside the network. They were all using the option 66 address as their Default Gateway. DHCP was not setting the gateway option (Option 3), so none of the machines knew how to get out. I added an “Option 3” (IIRC) setting to the dnsmasq.conf file (which should not be edited) and the machines started working. I also had to add DNS settings for the DHCP server so that the machines could get to where they needed to go.

There’s no easy way to set some of these common settings in the DHCP server screen. Also, the DNS Server option in the DHCP screen could use some more explanation.

Everything’s working now, so there’s no problem. Just thought I’d report a little hair-pulling using the Sysadmin Pro tool.


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