sundance-communications.com/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones Help! Can't network system anymore!

I still say it's an IP messaging problem . The server/router sees the IP address but does not know how to route it through call control . My 2 cents again .

I know this sounds crazy but have you tried putting a cheap router at each end and DMZing it? That's weird about the adressing, also if you remove the gateway adress at each site can you still ping the other site like you were on a local network? Cable is wierd like that.

NFC & OBTW might be on track and me not knowing Vodavi, are the TCP & UDP ports forwarded accordingly? Subnet & Gateway should not be the problem you are encountering. Subnet is just another hexidecimal address and Gateway is just an address for the main path. What brand of routers are these sites using? If you say CISCO, there lies the source of the problem because a new rule table has not been written for the new IP address, etc. Do a search on Sundance for BrianVoip and PM or e-mail him for his opinion. He's the best you will ever find knowledge wise on networking and data.

That's just it; we aren't using any routers at all. Both sites were just connected directly to the cable modems at both ends and they worked just fine for over a year. Since they were in different geographical areas of the county, Cox had them residing on different gateways and subnets, so there wasn't a problem. Now that they are across the street is when the problem came along.

We have had a conference call between the director of of Tech Support at Vodavi and a field engineer from Cox on Friday afternoon. They have mutually figured out that this is definitely a limitation on the Cox side and Cox will be contacting me Monday with a solution. I have known this engineer at Cox for several years and I am confident that if he can't figure out a solution, then it simply can't be done.

I was not mentioning onsite routers since you said cable modems in the beginning . Sounds like you have a good tech/engineer helping you now and hope all gets resolved soon !

It sounds like Cox is using Private VLANS, which allow them to isolate users on the same subnet from seeing each other. Cox should be able to configure a group of addresses as part of the same private VLAN, which would allow them to talk to each other.

Since you say the sites are right across the street from each other, it might be worth while to investigate other technologies, such as point-to-point wireless, or free space optical.

If done right, this could also allow them to bridge their LAN's between buildings.

Hope you got a resolution. I agree with the above, with true dual ethernet ports router(s) and proper static routes you should be able to have connectivity. Ed, I posted in the software section a topic on freesco, which would provide a quick bench testing solution.

With private VLANs, it dosen't matter if there is a router or not, the way the network is configured, users can pass traffic to/from the gateway, but not to other users on the same subnet.

The provider should be able to group multiple users into the same private VLAN, but until they do, it's like the other users don't exist.

I can think of a couple possible solutions, but they all involve a third location, and additional equipment at each site. basicly you would use a router at each site to push traffic thru a VPN to a third site on a different network, which would route between the two VPNs.

The best solution would be to either move off the cable modems to a point-to-point link of some sort, thus bypassing Cox entirely, or having Cox group the two sites as part of the same VLAN.

That's exactly what the ISP is going to do. They are creating a VLAN for this customer with 16 different static IP's on each side and separate subnets. All for the low low price of $25.00 per month on each end. Fortunately, this is only a short-term situation until both sites combine into one location, so the money won't be too hard to swallow.

I still think it stinks that the customer has to pay MORE to move their locations closer together!

As always, thanks to all of you for your insight. At least I now have information for the next time this happens.

Ed - I'm curious about this. Could you PM me the last Octet of both addresses and the subnet mask you are using? It's hard to believe that the ISP would tell you it's acceptable that one public address can't talk to another one that they provide. I'm wondering if the problem could be solved by changing the subnet mask (and thereby narrowing the subnet).