Category Archives: Telephony

Google Voice + Incredible PBX + OBi 110


UPDATE #3 (6/21/2019):
I did some digging and found the core issue (which has been talked about on other forums). In March Google disabled Google Voice access via the ‘https://www.googleapis.com/auth/googletalk’ API. They are only allowing access via a private ObiTalk API now. You basically have to get the OAuth client ID, client secret, and a refresh token for this ObiTalk app. Once you have these three things they can be used in the procedure below. After this you will be up and running again. Thank you again, naf!

UPDATE #2: As of 3/25/2019 my GVSIP trunk is showing a rejected status again. This time it seems the actual server is rejecting authentication. This is the error I am receiving in the Asterisk logs:

[2019-03-25 11:26:42] DEBUG[7278] res_pjsip_outbound_registration.c: Registration re-using transport 0x7ff23001f748
[2019-03-25 11:26:42] WARNING[7278] res_pjsip_outbound_registration.c: Fatal response '403' received from 'sip:obihai.sip.google.com' on registration attempt to 'sip:gv1143131xxxxxxxxxx@obihai.sip.google.com', stopping outbound registration

UPDATE: As of 3/19/2019 my GVSIP trunk was showing a rejected status. It seems that this version of IncrediblePBX was using a static IP for the outbound proxy which just stopped working. After looking into it more I realized the ‘nafkeys-update’ script updates this for you, but I didn’t use that script since it can no longer download the certificates. I have updated the steps (step 5) below to show how to resolve this. This was the error I was receiving in the Asterisk logs:

[2019-03-19 08:32:52] WARNING[3715] pjproject:                        SSL SSL_ERROR_SSL (Handshake): Level: 0 err: <336151568>  len: 0
[2019-03-19 08:32:52] WARNING[3716] res_pjsip_outbound_registration.c: No response received from 'sip:obihai.sip.google.com' on registration attempt to 'sip:gv1143131xxxxxxxxxx@obihai.sip.google.com', retrying in '60'

If you were already running this setup and you are now having this issue run the following commands to replace the static IP with the proper address:

  • sed -i ‘s|64.9.242.172|obihai.telephony.goog|’ /etc/asterisk/pjsip_custom.conf
  • amportal restart

 

I have been using a cordless house phone in conjunction with Google Voice ever since purchasing a home a number of years ago. This was accomplished using an OBi 110 device, but recently stopped working last year because Google updated certificates on their end and this model device did not trust this new certificate chain. OBi stated the box was end of life and they would not offer an update. At that time I setup a FreePBX instance between my OBi 110 and GV, but recently has Google ended XMPP support which nuked my new configuration. OBi now has a relationship with Google and conveniently offers a new model that works with Google Voice’s new SIP protocol (GVSIP). I have already had to replace my OBi once due to a hardware issue and they did not offer a simple update to fix the certificate issue last time. I am not willing to shell out more money to get this working. I searched the internet for options (surly if Google Voice is using SIP now there is a way to connect to it). A contributor to the Asterisk  project (the core of FreePBX/Incredible PBX) named naf has already developed a way to connect Asterisk to GVSIP. The problem is forums are removing references to files and instructions because of Google ToS violations. I spent some time figuring all this out and was able to hook my OBi 110 device up to an Incredible PBX VM. The VM has a GVSIP trunk and everything is working perfectly (hopefully for a long time). The steps are basically installing CentOS, installing Incredible PBX, obtaining a OBi certificate/private key pair (Google is using it to whitelist SIP connections), configuring the PBX trunks/routes, and configuring the OBi to talk to the PBX over SIP. Here are the steps I took to get this running:

  1. Download/install CentOS 6.10 minimal and Incredible PBX 16-15 (http://nerdvittles.com/?p=27089). As I said before I deployed this to my ESXi cluster at home, but this could easily run on a local VM. I’m looking into translating this setup into a Raspberry Pi deployment
  2. Obtain Obi client certificate/private key pair
    • All references to the certificates have been removed. You can actually pull the certificate and private key off of an OBi 110 and use this on Incredible PBX. This requires modified firmware (using a firmware patch). This patch process involves using bsdiff to patch the original firmware file with the aforementioned patch file, flashing the device with the patched firmware file, setting up a syslog server, configuring the syslog server on the OBi, initiating a device backup (which will send the cert/key in binary DER format to the syslog server), and converting cert/key pair to PEM
    • I will save you some time and provide you with the already patched firmware here, but I cannot publicly provide the certs for legal reasons (you can try dropping me a message). OBi 110 devices are available extremely cheap on eBay as they are now defunct. An OBi type device will be necessary for connecting GVSIP to a traditional phone anyway
  3. Copy the certificate pair to Incredible PBX (obihainaf.crt + obihainaf.key) under /etc/asterisk/keys
  4. Create a Google Voice refresh_token for your account. You will use the Incredible PBX OAuth Client ID and OAuth Secret found at /etc/asterisk/pjsip_custom.conf
  5. Obtain an ObiTalk-based OAuth client ID, client secret, refresh token. If you have access to a newer Obi device you can possibly install custom firmware that will allow you to SSH to it and pull these values for reuse. You can technically recreate the ObiTalk OAuth exchange and get a refresh token that way, but that is something that can’t be publicly posted. I will say that the ObiTalk OAuth client ID is: 565436231175-v2ed4f21arki7dt43pks0jlsujatiq2i.apps.googleusercontent.com
  6. Run the following commands to update the install-gvsip script with the ObiTalk OAuth client ID and client secret from step 5 (you can manually update the file if you don’t want to run the ‘sed’ commands):
    • sed -i ‘s|466295438629-prpknsovs0b8gjfcrs0sn04s9hgn8j3d.apps.googleusercontent.com|<CLIENT ID YOU OBTAINED IN STEP 5>|’ /root/gvsip-naf/install-gvsip
    • sed -i ‘s|4ewzJaCx275clcT4i4Hfxqo2|<CLIENT SECRET YOU OBTAINED IN STEP 5>|’ /root/gvsip-naf/install-gvsip
  7. Run the following command to update the install-gvsip script with the proper proxy address (you can manually update the file if you don’t want to run the ‘sed’ commands):
    • sed -i ‘s|64.9.242.172|obihai.telephony.goog|’ /root/gvsip-naf/install-gvsip
  8. Create your GVSIP trunk(s). You will be prompted for the refresh token you retrieved in step 5
  9. Verify trunks registered and working
    • cd /root/gvsip-naf/
    • ./show-trunks
  10. Setup the OBi 110 as an extension in Incredible PBX and set the OBi 110 to connect to Incredible PBX
  11. Configure inbound and outbound routes to the OBi 110 extension
  12. Configure SIP local networks in CIDR format under Settings -> General SIP Settings -> NAT Settings -> Local Networks. I had issues with my SIP services shutting down right after boot up in Incredible PBX and traced it back to this in the logs. I added my home subnet (192.168.0.0/24) and it stopped going down
  13. Test inbound and outbound calls

Note: This could also be deployed to a Raspberry Pi 3. I just didn’t have an unused Pi 3 handy, so I went with a VM. I was running my previous FreePBX instance on an older Pi B+ for over a year.