DHCP option 66 not working - reason due to logged-in user being deleted / phone IP blacklisted

[Mark Phillips]

Hi All,
I am not looking for any help with an issue, rather posting this in case it helps someone in the future.

I've experienced a few issues where a factory-reset Yealink T42S (although this won't be specific to this phone) fails to pick up the DHCP 66 provisioning URL. Enabling syslog via the T42S web portal reveals that it does attempt to retrieve the provisioning file, but receives HTTP error 403 (access denied). The file is confirmed to be accessible from another device, such as a web browser.

This then lead me to the IP blacklist where I found the phone's IP denied/blocked due to too many failed registration attempts. The reason for the failed registrations (in my case) is because the logged-in user has been deleted from the extensions list.

Ensuring the phone's IP is added as an "allow" entry on the IP blacklist (or at least, deleting the deny entry) will resolve the failure to retrieve the provisioning URL.

Hope this helps someone.

 

[SteveITS]

Good catch. I think the very first phone I ever went to reassign, I deleted it, and immediately realized I should have written down the web password first. So now I do that, delete it, and immediately factory reset the phone via its web interface (if remote). That way it's not trying to log in.

 

[leejor]

Ensuring the phone's IP is added as an "allow" entry on the IP blacklist (or at least, deleting the deny entry) will resolve the failure to retrieve the provisioning URL.

Years ago, after finding some ATAs had become blacklisted, for still undetermined reasons, I simply whitelisted my entire local LAN.