Avaya J100 Series IP Phones9600 Series IP Deskphones support configuration of network parameters using DHCP as per RFC 2131. However, when a DHCP server becomes unreachable and the DHCP lease currently held by the phone expires, the phone continues to use the same lease until the DHCP server becomes reachable. This functionality is controlled by setting the following parameter:

When this feature is enabled (DHCPSTD=1), the phone continues to use the lease data, including IP address, router and other options if the lease could not be renewed. In this state, the phone will attempt to reach a DHCP server every 60 seconds. When a DHCP server becomes available and a lease is renewed or new lease obtained, the phone performs a duplicate address detection on the offered IP address. If no conflicts are detected, this IP address is assigned to the local network interface for use.