I did manage to get a workaround going, so I will mark it as an answer. Travis: You are correct that their is an option to reduce the number of DHCP requests coming from the phone, I did consult MiTel regarding this and afgter an adjustment, there was no change. Even without any options set, the phones would not get DHCP. Additionally I had this problem with other lines of phones (MiTel and Yealink).

Philip_W: I set options 125 only as I was told by MiTel that 128, 129, and 130 are not needed. If I change the DHCP server to no longer be on the Windows server and instead be on my Router, it works fine.Īny clue as to why only my phones won't pull DHCP? I also tried deactivating the scope on one Server 2012R2 installation and installing a new role on another server as well as another scope, still the same result. I simplified the setup as much as possible so the server is directly plugged in to the same switch (unmanaged) as the phones. I confirmed that the DHCP server gets the discovery packet, but as that 20287 states, it never sends ACK or an offer to the phones. I ran a wireshark from the DHCP server as well as the phone. All other devices (Apple, Linux, IPhones, Android devices) get a proper DHCP. As in both MiTel and Yealink phones sit at 'Waiting for IP address'.

What is very strange is that the only devices not getting DHCP from this scope are VoIP phones. I expanded the scope (although it wasn't out at the time) and currently have about 60 addresses available. This could be because of IP address ranges of a policy being out of available IP addresses. Here is the error we get:ĭHCP client request from 08000FB342BE was dropped since the applicable IP address ranges in scope/superscope SCOPENAME Scope are out of available IP addresses. We are having an issue where DHCP addresses are no longer being handed out and the DHCP error 20287 is logged.

Mitel phones for voip