Subnet configuration

Parameter

Explanation

Gateway

Gateway IP address of the subnet.

Subnet mask

32-bit number that masks the IP address, and divides the IP address into network address and host address.

Enable

Primary DNS server

Address of the primary DNS server (entry is read from the DNS server).

Secondary DNS server

Address of the secondary DNS server (entry is read from the DNS server).

First IP address

First address of the address range controlled by the DHCP server.

Last IP address

Last address of the address range controlled by the DHCP server.

Lease time

Time frame provided to the user to work with a certain IP address. Before the validity period expires, the DHCP clients (e.g. system phones) notify the DHCP server whether they want to maintain their link. Once the validity period has expired, the DHCP server extends the validity of all the links for which it received such requests and resets the timer for the validity period. All links for which no request was received are disconnected and the corresponding IP addresses are released.

Relay option

A DHCP Relay can be configured to add a Relay Agent Information (Option 82) into the forwarded DHCP Discover message. It is recommended that the same information is entered in the DHCP server. The option 82 string is entered in HEX format.

A relay agent sends an option 82 (example: 01 0b 00 02 00 16 45 53 2d 34 31 32 34). This string is entered in the subnet settings without spaces (example. 010b0002001645532d34313234)

For a subnet, if the MiVoice Office 400 DHCP server has the DHCP Relay Option configured and now receives a DHCP Discover message without option 82 or with a wrong option 82, then it ignores the DHCP Discover and doesn’t send an “Offer” back