Registration/420 Bad Extension code (clear or delete SIP Proxy-Require field in your ATAs/SIP clients)

[Liptonbrisk]

"Hi,

In the last 24 hours there have been a few issues with Freephoneline's sip proxies due to invalid sip packets overloading the parser and causing a crash and restart.

Due to this we have enabled the sanity check module on them which prevalidates the sip headers before processing and will drop the connection of they do not pass.


The main ones we are seeing rejections for currently right now are

1. Body length not matching content length

2. Invalid proxy require header being sent."

-- Fongo admin

[Liptonbrisk]

For Linksys/Cisco ATAs

Don't use $PROXY for your (CISCO/Linksys) ATA's SIP Proxy-Require field. Don't enter anything there. Keep that field blank when using Freephoneline. Also, while I'm not positive that modified User-Agent values are creating issues, User-Agent should be set to $VERSION, and SIP Reg User Agent Name should be blank.

How to check?

I. Access your ATA's WebUI

a) Dial ****
b) Then dial 110#
c) Enter the IP address you hear into a web browser.
d) Login to your ATA.
e) Always choose the admin login and advanced view menus (select "advanced" in the upper right).

For SPA122 (and other ATAs that have a router), you may have to enable remote management first: dial ****7932# followed by 1 to enable Remote Management. By default, Remote Management is disabled on SPA122, so browsing to that IP is blocked. You would have needed to change the default admin password for the ATA first. Afterwards, you can Dial ****7932# followed by 1 to enable Remote Management (you should confirm that it's enabled under Web Access Management in the UI), and then browse to the IP announced after dialing ****110#. After enabling Remote Management, ensure the Remote Management Port is set and that Admin and Web Utility Access are enabled. Those settings are on the SPA122 Web Access Management page.

For Linksys RT31P2, try logging in at http://192.168.15.1/Voice_adminPage.htm
Or try adding "/Voice_adminPage.htm" (without the quotation marks) after the Linksys RT31P2's LAN IP in a web browser.


II. Navigate to the Voice-->Line tab

a) Click the Voice tab at the top
b) Then click Line 1 (or whichever line is configured for Freephoneline)
c) Scroll down to the SIP Settings section.
d) Look for a field called "SIP Proxy-Require".

That field may, incorrectly, contain $PROXY (don't use macros); a hostname, such as voip.freephoneline.ca (or oddly some server from a different VoIP service provider); or an IP address. That's not what you want.

e) Delete everything in that SIP Proxy-Require field so that it is completely blank. Do not put anything in that field; it should always be empty for Freephoneline.

f) Submit changes (click appropriate button).


III. Fix wrong User-Agent and SIP Reg User Agent Name

If you’re also seeing User-Agent is set to PROXY or anything other than $VERSION, change the global SIP User Agent fields (these are not on the Line page for SPA3102/SPA2102. Cisco documents them under Voice -->SIP -->SIP Parameters).​

a) Navigate to Voice --> SIP.​

b) Under SIP Parameters set the following:

i) SIP User Agent Name should be $VERSION (Linksys/Cisco’s default-style macro value)​

ii) SIP Reg User Agent Name should be blank.​

c) Submit changes (click appropriate button).



IV. Prevent old provisioning from re-breaking your service

If this ATA was previously provisioned by another provider, it may re-download the bad values on reboot. Cisco/Linksys provides a Provisioning section where “Profile Rule” can point at a provisioning URL, which you don't want.

a) Navigate to Voice --> Provisioning.​

b) Set "Provision Enable" to "no".

c) Set "Resync on Reset" to "no".​

d) Set "Resync From SIP" to "no".

e) Check Profile Rule (and similar rule fields). If it points to servers, clear it.

(That is, delete Profile Rules).

f) Submit changes (click appropriate button).


V. Save and reboot

a) Click "Submit All Changes" (or the equivalent Save button for your ATA's model).
b) The ATA should reboot and re-register. If the ATA does not reboot, power cycle it (turn it off and on).

[Liptonbrisk]

For Obihai ATAs (including Poly 4xx series ATAs) and Obihai IP phones

I doubt that anyone has entered anything for X_ProxyRequire or changed X_UserAgentName in Obihai ATAs (or Poly 4xx series ATAs) or Obihai IP Phones, but, just in case, check:

I. a) If you have an OBi202 or OBi302 (and Poly 402, I believe), ensure that AccessFromWAN is enabled in the ATA in order to log into it via WebUI.

Dial ***0 from the phone connected to the OBi202/OBi302
- Enter 30#
- Press 1 to Enter a New Value
- Press 1# to Enable
- Press 1 to Save

b) Now dial ***1. Enter the IP address you hear into a web browser if you want to use your Obihai device's web interface instead of Obitalk.com. Login. Default username and password are “admin” without the quotation marks.

II. Delete any entry for X_ProxyRequire (should be blank by default).

a) Navigate to Service Providers--> ITSP Profile A (or the profile you’re using for Freephoneline) --> SIP
b) Find X_ProxyRequire, and make it blank (empty). It should be blank by default.
c) Click the "submit" button, and then click the "Reboot" button to reboot your ATA/IP Phone.


III. Fix corrupted SIP User-Agent (If you have changed from the default value)

a) In the same place (Service Providers-->ITSP Profile used for Freephoneline-->SIP), find X_UserAgentName.
b) Default should be OBIHAI/${DM}-${FWV} (or similar). If you've changed from the default value, revert to the default value.
Note that ${DM} and ${FWV} are OBi macros (Device Model and Firmware Version), and macro expansion is supported in parameter values.
c) Click the "Submit" button.

IV. Stop old provisioning from re-breaking

If this ATA was previously provisioned by another provider, it may re-download bad values on reboot.

a) Navigate to System Management--> Auto Provisioning
b) I would change every Method setting listed on this page to "Disabled" to help avoid having anything changed without your knowledge or permission.
c) Click the "Submit" and "Reboot" buttons. The ATA should reboot and register.

[Liptonbrisk]

I don't own Grandstream devices, but I'm not seeing anything that allows users to inject their own "Proxy-Require" header or something similar in the WebUI for Grandstream ATAs. If I ever discover there's a setting I've missed, I'll update this post.