I’m trying to help out a friend’s office network. I’m going around and around with their ISP’s technical support staff to try and get an issue fixed.
Here’s the story…
They have commercial T1 service with an ISP. Their old employee no longer works there. They haven’t got a clue as to how things are setup or whatever.
They have a SonicWall firewall. It is acting as NAT and DHCP. The LAN side is using a public IP that ends in 242, and they use a passthrough on another IP to a web server, and that IP ends in 243.
This setup worked for them for about a year or more. Then 243 stopped working, the website was unreachable, and they couldn’t browse out on it.
This is when they called me. So I called their ISP, and they told me that the IP addresses I have are wrong. They are designated for equipment. And that the range I should be using starts with a 97. So, I logged into the SonicWall and changed everything to use the new IP range, as well as new Gateway, and new Subnet. But it didn’t work.
I was then told, that we lack a router. The 242 number is supposed to be assigned to a router, the router then distributes the 97 numbers to the other equipment (Such as the SonicWall).
This is the part I’m unsure of, and need someone to tell me that it’s correct.
The ISP assigns me two sets of public IP addresses. One set is for equipment like the router. So it looks like this…
The second set of IP addresses is for distribution to other equipment behind the router. And it looks like this…
I assume, I then add the 97 address to the WAN IP in the SonicWall.
Is this right? Is that how it normally works? I’m used to home routers where you get an IP address and that is it, none of this two IP address stuff, so I’m a bit confused by what they are telling me, and before I tell them they need to go out and buy a router, I want to make sure my facts are straight.