Dell Force10 S55T FTOS Command Line Reference Guide for the S55 System FTOS 8. - Page 525

Parameters ip-address default-vrf Enter an IP address in dotted decimal format (A.B.C.D). (Optional) E-Series Only: Enter default-vrf for the DHCP server VRF is using. Defaults Not configured. Command Modes INTERFACE Command History Version 8.3.5.0 Version 8.1.1.0 Version 7.9.1.0 Version 7.6.1.0 Version 7.5.1.0 pre-Version 6.2.1.1 Introduced on the S55. Introduced on E-Series ExaScale Introduced VRF on the E-Series Added support for S-Series Added support for C-Series Introduced on E-Series Usage Information You can add multiple DHCP servers by entering the ip helper-address command multiple times. If multiple servers are defined, an incoming request is sent simultaneously to all configured servers and the reply is forwarded to the DHCP client. FTOS uses standard DHCP ports, that is UDP ports 67 (server) and 68 (client) for DHCP relay services. It listens on port 67 and if it receives a broadcast, the software converts it to unicast, and forwards to it to the DHCP-server with source port=68 and destination port=67. The server replies with source port=67, destination port=67 and FTOS forwards to the client with source port=67, destination port=68. ip helper-address hop-count disable c e s Disable the hop-count increment for the DHCP relay agent. Syntax ip helper-address hop-count disable To re-enable the hop-count increment, use the no ip helper-address hop-count disable command. Defaults Enabled; the hops field in the DHCP message header is incremented by default Command Modes CONFIGURATION Command History Version 8.3.5.0 Version 8.1.1.0 Version 7.6.1.0 Version 7.5.1.0 Version 6.3.1.0 Introduced on the S55. Introduced on E-Series ExaScale Added support for S-Series Added support for C-Series Introduced for E-Series Usage Information This command disables the incrementing of the hops field when boot requests are relayed to a DHCP server through FTOS. If the incoming boot request already has a non-zero hops field, the message will be relayed with the same value for hops. However, the message will be discarded if the hops field exceeds 16, to comply with the relay agent behavior specified in RFC 1542. IPv4 Routing | 525