Using a BOOTP or DHCP Server

The switch contains a BOOTP and DHCP client, so if you have a BOOTP or DHCP server in your IP network, you can have it assign IP addresses to the switch. This is more likely to be desirable on the switch's VLAN mgmt than it is on any other VLANs.

If you are using IP and you have a Bootstrap Protocol (BOOTP) server set up correctly on your network, you must provide the following information to the BOOTP server:

  • Switch Media Access Control (MAC) address, found on the rear label of the switch
  • IP address
  • Subnet address mask (optional)


Dual network operating system ExtremeSwitching switches (for example, 5520 switches) when running ExtremeXOS use a base MAC address at offset 0 (for example: 00:c0:cc:8b:68:00) for both the OOB management port as well as inband VLANs using DHCP. However, when running VOSS, the offset is 0x81 for OOB (for example: 00:c0:cc:8b:68:81) and 256 (for example: 00:c0:cc:8b:69:00), assuming the first VLAN MAC offset 0 is assigned to the inband VLAN. If a different VLAN MAC offset is assigned, this MAC address changes accordingly (for example, if VLAN MAC offset is 10, then the associated MAC address is 00:c0:cc:8b:69:0A).

When using DHCP client on the switch, the switch sends a common DHCP client identifier equal to the base MAC address of the switch that is printed on the switch label. When transitioning between VOSS and ExtremeXOS, since the DHCP client ID is the same, the same IP address should be given out by the DHCP server assuming a standard DHCP pool configuration. If you want to statically assign IP addresses on the DHCP server, then it is recommended to assign them based on the DHCP client ID, since this ensures the binding does not change when alternating between VOSS and ExtremeXOS. If the DHCP IP addresses are assigned based on MAC addresses, multiple entries have to be configured (one for 0x81 offset, and one for :00 offset) to account for differences in the OOB or inband VLAN source MAC address usage between the two operating systems.

The switch does not retain IP addresses assigned by BOOTP or DHCP through a power cycle, even if the configuration has been saved. To retain the IP address through a power cycle, you must configure the IP address of the VLAN using the CLI or Telnet.

If you need the switch's MAC address to configure your BOOTP or DHCP server, you can find it on the rear label of the switch. Note that all VLANs configured to use BOOTP or DHCP use the same MAC address to get their IP address, so you cannot configure the BOOTP or DHCP server to assign multiple specific IP addresses to a switch depending solely on the MAC address.