Name
ip forward-protocol — global
Synopsis
ip forward-protocol {udp [port] | any-local-broadcast | spanning-tree |
turbo-flood}
no ip forward-protocolConfigures
Forwarding of broadcast packets for certain services
Default
Enabled with the ip helper-address command
Description
When the ip helper-address command is configured for an interface, the router “helps” hosts find certain UDP services by forwarding the packets. These services are BOOTP (DHCP), DNS, TFTP, TACACS, TIME, and NetBIOS name and datagram servers. This command allows you to define additional UDP ports that you want forwarded automatically to the helper IP address.
-
port Optional. Without this parameter, all the default UDP ports listed here are forwarded. This keyword allows you to forward a specific port. You can disable a default port with the
noversion of this command.-
any-local-broadcast Forwards any broadcasts including local subnet broadcasts.
-
spanning-tree Forwards IP broadcasts that meet the following criteria: First, it must be a MAC level broadcast; second, it must be an IP level broadcast; and third, it must be TFTP, DNS, NetBIOS, ND, TIME, BOOTP, or any other UDP packet specified by an
ip forward-protocol udpcommand.-
turbo-flood Speeds up the flooding of UDP datagrams when using the spanning-tree algorithm. This command should be used in conjunction with the
ip forward-protocol spanning-treecommand.
Example
To forward port 21000 for a specific application:
ip forward-protocol udp 21000