Hi there,
I have just had a phone system installed in two schools, School A & B. School A users are experiencing intermittent silences. The call audio randomly drops out for 2-5 seconds and then comes back in. School B does not have this issue at all unless they're calling School A's extensions.
I have listened to a call recording and i can hear both voices on the call but it just seems that School A cannot hear the other person. The handset is fully silent/dead.
This also is the same for people using the APP / Webclient on our Wi-Fi/LAN. The silences can occur there too - These are that random that somedays people may not even complain, then some other times its insane.
I will try to explain the setup as best as i possibly can.
Setup
We have an onsite Smoothwall (Firewall).
I have allowed everything for 172.17.1.0/24 outbound so i can't believe there is any filtering issues and had Smoothwall tech support looking around and nothing nothing untoward that would filter packets.
What i have tried:
School B does not have any port forwarding and everything is working as expected.
Any help would be great! I am in the process of getting Virgin to turn on another interface on the router for me, but its an expensive change just to rule out the issue being the Firewall. I am now at a stage where the only thing i can test now is to get all the ports, somehow on their own switch and bypass my firewall network all together.
I currently have a laptop mirroring a port with a phone in so i am capturing all traffic, however i don't know Wireshark good enough to determine where the issues are. All suppliers (Virgin, my networking support & the phone company) are in their own ways saying the issue isn't theres.
Any hints to what to try now would be fantastic!
Thanks.
I have just had a phone system installed in two schools, School A & B. School A users are experiencing intermittent silences. The call audio randomly drops out for 2-5 seconds and then comes back in. School B does not have this issue at all unless they're calling School A's extensions.
I have listened to a call recording and i can hear both voices on the call but it just seems that School A cannot hear the other person. The handset is fully silent/dead.
This also is the same for people using the APP / Webclient on our Wi-Fi/LAN. The silences can occur there too - These are that random that somedays people may not even complain, then some other times its insane.
I will try to explain the setup as best as i possibly can.
Setup
We have an onsite Smoothwall (Firewall).
- All phones are on VLAN 400 and on an IP range 172.17.1.0/24
- Smoothwall has a VLAN 400 interface and that goes into the main switching which in turn goes out onto the internet.
- Usual routing for outbound calls : Phone => 3CX SBC => Smoothwall => Virgin Router
- (Both Schools are set up identical)
- I have just found out that our ISPs have SIG ALG enabled but School B, doesn't have this issue?
I have allowed everything for 172.17.1.0/24 outbound so i can't believe there is any filtering issues and had Smoothwall tech support looking around and nothing nothing untoward that would filter packets.
What i have tried:
- Fully allowed 172.17.1.0/24 range on the firewall both incoming outgoing.
- PBX delivers Audio setting is ON.
- Taken the PC out of the phone and seperated the ports, marking the port as UNTAGGED only.
- Put the phones onto our flat native network - filtering occurs on the firewall but the silences do not seem to be any worse.
- Checked the Codecs based on our phones (Yealink T40G's). - All seem fine.
- To replicate the silences, i have played music down the phone while running a packet trace:
- Playing down one phone at a time, there were no silences
- Playing down both phones, silences were inserted - the quality was terrible. Could this be a thing? (Wireshark was reporting a 4% packet loss spike)
School B does not have any port forwarding and everything is working as expected.
Any help would be great! I am in the process of getting Virgin to turn on another interface on the router for me, but its an expensive change just to rule out the issue being the Firewall. I am now at a stage where the only thing i can test now is to get all the ports, somehow on their own switch and bypass my firewall network all together.
I currently have a laptop mirroring a port with a phone in so i am capturing all traffic, however i don't know Wireshark good enough to determine where the issues are. All suppliers (Virgin, my networking support & the phone company) are in their own ways saying the issue isn't theres.
Any hints to what to try now would be fantastic!
Thanks.
