SIP and NAT without proxy or a NAT aware app is a no starter. SIP is a great protocol until you get a NAT firewall in the middle. Even if you manage to get your IP correctly registered the RPT (UDP protocol that carries the voice packets) will still be broken. So unless you have control of your work firewall (or a vpn to your home network from your phone) don’t even try. It will be a very painful and futile experience. You may have better luck with an IAX client. From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org] On Behalf Of Robert Newberry Sent: Friday, June 20, 2014 1:20 PM To: app_rpt-users@ohnosec.org Subject: [App_rpt-users] Zoiper registering problems I can register my SIP zoiper account from my home wifi and LTE. At work on the WiFi I can not register, but if I turn off WiFi the SIP account will register on LTE. I watched the CLI and I think I see the problem, but don't quite understand how to fix it and maybe someone can help. Here is what I get. -- Registered SIP '7252' at 70.XXX.X.XX port 4446 expires 60 [Jun 20 13:04:48] NOTICE[2177]: chan_sip.c:12758 handle_response_peerpoke: Peer '7252' is now Reachable. (199ms / 2000ms) -- Registered SIP '7252' at 192.168.125.104 port 49121 expires 60 -- Unregistered SIP '7252' [Jun 20 13:05:51] NOTICE[2177]: chan_sip.c:16258 sip_poke_noanswer: Peer '7252' is now UNREACHABLE! Last qualify: 0 -- Registered SIP '7252' at 192.168.125.104 port 49121 expires 60 -- Unregistered SIP '7252' -- Registered SIP '7252' at 192.168.125.104 port 49121 expires 60 [Jun 20 13:06:00] NOTICE[2177]: chan_sip.c:16258 sip_poke_noanswer: Peer '7252' is now UNREACHABLE! Last qualify: 0 N1XBM*CLI> It looks like when I register on LTE it shows my actual IP address and then pokes me and deems me "reachable". When I connect using WiFi I'm connecting but when it tries to poke me its using an IP that's private and behind me firewall. Also from my phone I show a time out and a 408 error for time out. I also took it a step further and installed zoiper on my laptop and connected to the same WiFi and my laptop connects and shows the IP address of my actually cable modem. Very confused, if anyone can help I would appreciate it. Thank you