Ghost Recall when using PJSIP and Yealink phones.

[JaredBusch]

System I migrated over the weekend came up with a new problem that I have not dealt with before.

I posted on the Yealink forums, so hopefully I will get an answer.
http://forum.yealink.com/forum/showthread.php?tid=40843

Anyway, if you transfer a call to another extension and you are using PJSIP (the new standard for SIP communication in Asterisk), you can get a ghost ring back after a transfer to another extension that goes to voicemail.

A little Googling led me to these two threads that already identified the problem for me.
https://community.freepbx.org/t/transfered-calls-from-the-operator-are-being-transfered-back-ghost-call/36205/31
https://community.asterisk.org/t/transfer-recalls-via-refer-notify-events/69764

So I took a PCAP and sure enough. there it is.

Looking into how to apply the custom rule within the designed method for adding custom rules.

The GUI has a setting I can enable for this, but I am not seeing a Syntax example.

[JaredBusch]

And there we go. Will test tomorrow.

Enable the setting pictured above.

Then open SSH as root

nano /etc/firewall-4.rules

put in the rule with the normal iptables syntax, less the actual iptables command.

-I OUTPUT -m string --string "SIP/2.0 503 Service Unavailable" --algo bm --to 65535 -j DROP

Save and close and then restart the firewall.

fwconsole firewall stop
fwconsole firewall start

Tail the firewall log to make sure it is picking it up.

[root@bpbx ~]# tail -f /tmp/firewall.log 
1494374195: /sbin/iptables -A fpbxhosts -s 127.0.0.1/32 -j zone-trusted
1494374195: /sbin/ip6tables -R fpbxlogdrop 1 -j DROP
1494374195: /sbin/iptables -R fpbxlogdrop 1 -j DROP
1494374195: /sbin/iptables -N zone-external
1494374195: /sbin/ip6tables -N zone-external
1494374195: /sbin/ip6tables -A fpbxinterfaces -i eth0 -j zone-external
1494374195: /sbin/iptables -A fpbxinterfaces -i eth0 -j zone-external
1494374195: /sbin/iptables -t nat -A masq-output -o eth0 -j MARK --set-xmark 0x2/0x2
1494374195: Custom rule: /sbin/iptables -I OUTPUT -m string --string "SIP/2.0 503 Service Unavailable" --algo bm --to 65535 -j DROP
1494374195: Custom Firewall rules file /etc/firewall-6.rules does not exist, skipping

[JaredBusch]

Now just to wait on Yealink to respond to my post on their forum to see if they will acknowledge this as an issue or not.

[gjacobse]

@JaredBusch said in Ghost Recall when using PJSIP and Yealink phones.:

put in the rule with the normal iptbales syntax, less the actual iptables command.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ^^^^^

Just for my own - Is iptbales suppose to be iptables?

[JaredBusch]

@JaredBusch said in Ghost Recall when using PJSIP and Yealink phones.:

Now just to wait on Yealink to respond to my post on their forum to see if they will acknowledge this as an issue or not.

Yealink opened a support case based on my post. Will be getting the logs to them.

[JaredBusch]

Been working with Yealink support on this and after confirming this happening with the T46G and the T42G phones, their support upped the severity and I got an answer back to add the below setting to the configuration files.

transfer.hang_up_after_success_trans = 3

I did so on the T46G, disabled the custom firewall rules, and had the operator repeat the transfer.

No ghost ringback.

I'll leave the custom firewall disabled and see if it stays good all day.

I'll test in more detail over the weekend or on Tuesday, whichever time I have a tech on site.