sundance-communications.com/forum Forums VOIP Phones & IP PBX VoIP & Cloud Phones, Hosted PBX, General IP Phones Trouble with Toshiba VOIP

This is a real tough one. Even tho it is Toshiba VOIP, I'm sure it is a network issue, not a Toshiba issue. We have had 3 techs working on this for many hours. All of use are fairly network savey, others more then me. So if you can think of something;

At Issue- We have 3 VOIP connected to the system, 1 internal, 2 external. The external phones would occationally stop working, the one in the office always works fine..

One VOIP card runs all the phones and is assigned a Public IP. The customer has 5 IPs. They use one connected to their firewall. We use one for Voip.

There is no firewalls connected in front on the PBX's VOIP card.

When the external phones stop working, I can not PING the card from outside the network, but I can ping it when on site. While the phones all work, pinging from outside works fine.

The Internal Voip and PC are connected to a firewall with NAT, which is connect to a data swith along with the VOIP card, then to the Internet, so the Internal VOIP phone and PINGS go to the Hub and wouldn't leave the WAN to get to the PBX. The firewall and VOIP card are in the same subnet.

Their connection to the Internet is VIA a Wireless bridge. Their Internet never stops working.

I had put an old 10BT hub and used a packet sniffer. I could not see external ping requests to the VOIP card, only from the Routers IP addy when pinging from my PC on the inside network. Not sure if that is an accurate test or not. I was trying to prove that the external pings never make it to the building, much less to the PBX.


Anyway.. It looks like it is a network issue, but their IT guy says that it is our equipment for sure, and that "you don't need a PING for VOIP to work". Weird thing is, that when we reset the PBX VOIP card, the phones start to work again (and Pings work fine), which is why we replaced the card, with the same results. He says we should check out route tables. All we have is Default gatway. No routing tables.

Anyway, may be TOO much detail here, but I think something in the network. Network guy is saying it's use. Customer is really upset. Never had any issues like this before. Not sure how the Internet gets connected outside the wireless bridge.

Next step may be to try a different IP. They have a couple unused. Other then that, not what to do.

My initial reaction is the answer is in the wireless.

Do they have any wired internet connection available and or close ( i.e. - a neighboring business), that you could test it on?

Make sure your L/M IPU card has the latest firmware as does the CIX. Put a hub right in front of the IPU card. Next time this happens, run wireshark and filter for all traffic to that specific(IPU) address. If you don't see any traffic to it then the issue is in the network somewhere. Don't forget to uncheck tcp/ip protocol in Windows for your pc's network adapter.

Confirm latest firmware. So is PBX software. Firemare on phones can be updated, but the phone that always works has the same firmware version.

I actually did put a hub there (old 10 base t) and did run wireshark and could not see any outside trafic to the IP address of the LIPU, including the Ping requests from the outside. I used a website to do a reverse ping. When the phones work, I see all kinds of traffic from the outside, so I know the setup is capturing ok.

I thought it was network related from day 1. I was hoping to prove or disprove. I think I saved the Wireshark capture, but it still could be hard to prove that there was incoming traffic not showing up at that time.

I showed a Ping timeout from outside the network, while at the same time, ping ok from the inside. Network guy is still a hard sell. He wants to put his own VOIP system on customer site to prove his networks is working ok.

And at the same time he puts in his VOIP system in, the problems "magically" disappear! What is his explanation for the lack of any traffic to that IP? HMMMMMMMMMMMM!

For grins, try putting a small switch between the system and his network. See if that fixes it. I have seen scenario's where a switch and a NIC just didn't get along, and putting something like a 5-port 10/100 linksys switch in between fixed it. Also, when it starts screwing up, plug into this 5-port switch and see if you can do other things like surf the web.

What it sounds like to me is either the Network switch or phone NIC is going bad. You mentioned you already relplaed the phone side so i'm guessing it might be the network side.

Have you tried a different port on the network switch? And what kind of switch is it? How old? It's not uncommon for ports to go bad on switches.

This sounds like an address-conflict issue.

My costly solution:
Plug in a second LIPU, point the internal phones to that card and isolate the external card from any traffic except from the external phone and router - presto! Because all these tech hours may not be billable, the cost of a second LIPU may be more cost-efficient. Of course, you may never find the cause.

Troubleshooting current issue:
1)As mentioned, stick a hub in back of the router and capture everything going to the LIPU.
2)Change the external LIPU address to the last available address in the range to keep the phones operating. Set up a NIC with wireshark (filtered) on the problematic second address in your external range and capture.

I'm not the expert. I just work on phones.

Regarding the IT guy's explanation: How do you get a successful packet to the destination if you don't receive a reply?

Sounds like funky switch to me. If it was still pinging and not sending packets to the LIPU then it would sound like IP conflict. Could be both.

But putting a small switch/hub between the LIPU and the phone system you can determine if unplugging the phone system resets things and makes it work, or if unplugging the core switch does. This would atleast tell you what side of the conversation to definitively blame. If the core network switch maintains connection the the small switch and just unplugging and plugging in the LIPU fixes things then i'd say you have some kind of issue with the LIPU still. If the problem goes away then the issue is on both end's. If you leave the LIPU connected to the small switch but unplugging the core switch fixed it then i'd say you have a bad port in your core switch.

If you have an IP conflict then unplugging the LIPU when it disconnects and issuing a ping from a computer connected to the small switch should yield a reply.

I think we might be overlooking something here. What is the router they are using? The problem, as stated, is external to LIPU. I've have ran into problems with routers, since everyone wants some psuedo-level of firewall protection, deciding to just kill establish port connections in the name of security. How long after the link is up does it go down? We might be chasing the wrong end of the snake here.

I thought Newtecky said the LIPU had a Public IP address. If so a router may not have been necessary. So is the local IP phone operating as a remote phone targeted to the Public IP address of the LIPU? Something doesn't add up here.

Also double check the Subnet mask for the LIPU address. I resolved a similar problem recently that turned out to be an incorrect subnet mask.

Ya. the LIPU (the card the does all VoIP for the PBX) has a public IP. It is in the same Subnet as the Public IP for their Router for the PCs in house. One VoIP phone (which has always worked fine) on site LAN connects to their network router, then to a 5 port data switch, which the LIPU is connected. It is pointed to the Public IP of the LIPU (the IP card). There is no router in front of the IP card to the Internet.

I triple checked the Subnet. I figured it was OK otherwise it would never work. It goes down randomly from only after a few hours, to a couple days.

When the phones where not working, I put in an old 10BT hub. I think I temperarily replaced the 5 port swith that was there.

The phones started working again after I reset the systems LIPU card, which realy makes it looks like our system, but the onsite phone always works, and is connected to the same card. The only different is that the phone does not travel accoss the Internet.

Briefly here is how the network is connected (from what I can see);

{Internet}
....|......
Wireless
Bridge
....|.......
5 Port
Data Switch (WAN)
...|..........|.......
LIPU.......SonicWall firewall
for...........|......
VoIP........24 port Data (LAN)
.............for PCs

I did briefly disconnect the IP card and PINGed the IP, with no response. Their firewal does not respond to Pings. Our IP card (LIPU) will, and has when the phones work. The only network settings are IP, Subnet, and Gateway. All or OK.

Basically I'd like to either figure out what is wrong and fix it, or figure out what could be wrong on the Network side and tell their guy to fix it. I just can't figure out how our VoIP system can be the problem when the onsite phone, and Pings always work without a problem. We have not replaces the 5 port data switch yet. We have replaced the card. I really looks like the system (to the customer) because reseting the IP card (LIPU) fixes the problem. I just can't see how. Even when I can not ping the IP card from the outside, the Internet connection stay up fine.

Obviously there is some kind of router further upstream past the wireless bridge. The problem may be with the ISP for all I know. When no one was looking I briefly unplugged the wireless bridge, which didn't seem to fix the phones.


Thanks for all the responses. I've been racking my little brain on this one for a long time now.