I am using a FritzBox 7270 updated to version 74.05.53 (the latest currently available). My ISP assigns an IP address that FB reports as 172.22.245.245 which is a private IPV4 address. When I run a test from http://www.whatsmyip.org/ the resulting IP address is different from the one reported by FB (and this is my public IPv4 address which is pingable). I think that my ISP is using a NAT firewall and the FB is behind it.
I use a VOIP account from iptel.org to conduct tests. It is registered correctly in FB and its status lights up green. I can make outgoing calls to other ipTel users without any problems. The problem is that I cannot receive calls from other users. When someone calls he hears no dialling tone and after about 30 seconds he gets redirected to the answering machine.
There is however one exception. After I telnet in FB I issue the command voipd -s (to stop voip services) and then I issue the command voipd (to start the voip service again.). At this point if an external call is made within approximately 30 seconds then it gets through and the phone rings. Subsequent attempts result in failure to connect.
It seems to me to be a NAT traversal problem. Only the first registration goes through the NAT succesfully but subsequent ones fail. I have tried to change the following parameters in the voip.cfg file but they all fail in the same way as described before.
- I set is_nat_aware=yes instead of no
- I set ttl = 10m instead of 30m
- I set sipping_interval = 15s instead of 280s
- I set register_failwait = 10m instead of 30m
- I set stunserver = "stun.iptel.org" instead of "" (blank)
- I also tried setting the "Always register via an Internet connection" option via the web interface
I tried all above settings one by one and in combination but it never works.
Given that the ISP policy on the firewall cannot be changed the question is whether anything can be done on the FB to facilitate successful incoming calls. It appears that if there is a frequent enough registration request from the FB to the voip provider server then the NAT firewall is able to pass the calls to the correct private IPv4 address of the FB and incoming calls are possible. So the question is what settings to tweek in FB to try out.
Any help in this matter will be greatly appreciated, also from all those who have ISP firewalls blocking them.
Note 1: Skype calls work fine as well as P2P programs like bittorrent.
Note 2: Any answer in the German language is welcome as I can manage to read it but I am unable to answer back in German.
Thank you in advance.
I use a VOIP account from iptel.org to conduct tests. It is registered correctly in FB and its status lights up green. I can make outgoing calls to other ipTel users without any problems. The problem is that I cannot receive calls from other users. When someone calls he hears no dialling tone and after about 30 seconds he gets redirected to the answering machine.
There is however one exception. After I telnet in FB I issue the command voipd -s (to stop voip services) and then I issue the command voipd (to start the voip service again.). At this point if an external call is made within approximately 30 seconds then it gets through and the phone rings. Subsequent attempts result in failure to connect.
It seems to me to be a NAT traversal problem. Only the first registration goes through the NAT succesfully but subsequent ones fail. I have tried to change the following parameters in the voip.cfg file but they all fail in the same way as described before.
- I set is_nat_aware=yes instead of no
- I set ttl = 10m instead of 30m
- I set sipping_interval = 15s instead of 280s
- I set register_failwait = 10m instead of 30m
- I set stunserver = "stun.iptel.org" instead of "" (blank)
- I also tried setting the "Always register via an Internet connection" option via the web interface
I tried all above settings one by one and in combination but it never works.
Given that the ISP policy on the firewall cannot be changed the question is whether anything can be done on the FB to facilitate successful incoming calls. It appears that if there is a frequent enough registration request from the FB to the voip provider server then the NAT firewall is able to pass the calls to the correct private IPv4 address of the FB and incoming calls are possible. So the question is what settings to tweek in FB to try out.
Any help in this matter will be greatly appreciated, also from all those who have ISP firewalls blocking them.
Note 1: Skype calls work fine as well as P2P programs like bittorrent.
Note 2: Any answer in the German language is welcome as I can manage to read it but I am unable to answer back in German.
Thank you in advance.
