NOTE
The application names are the names for these applications that the Layer 3 switch software recognizes, and might not match
the names for these applications on some third-party devices. The numbers listed in parentheses are the UDP port numbers for
the applications. The numbers come from RFC 1340.
NOTE
Forwarding support for BootP/DHCP is enabled by default.
You can enable forwarding for other applications by specifying the application port number.
You also can disable forwarding for an application.
NOTE
If you disable forwarding for a UDP application, forwarding of client requests received as broadcasts to helper addresses is
disabled. Disabling forwarding of an application does not disable other support for the application. For example, if you disable
forwarding of Telnet requests to helper addresses, other Telnet support on the Layer 3 switch is not also disabled.
Enabling forwarding for a UDP application
If you want the Layer 3 switch to forward client requests for UDP applications that the Layer 3 switch does not forward by default, you
can enable forwarding support for the port. To enable forwarding support for a UDP application, use the following method. You also can
disable forwarding for an application using this method.
NOTE
You also must congure a helper address on the interface that is connected to the clients for the application. The Layer 3 switch
cannot forward the requests unless you congure the helper address.
To enable the forwarding of NTP broadcasts, enter the following command.
device(config)# ip forward-protocol udp ntp
Syntax: [no] ip forward-protocol {udp udp-port-name | udp-port-num }
The udp-port-name parameter can have one of the following values. For reference, the corresponding port numbers from RFC 1340
are shown in parentheses. If you specify an application name, enter the name only, not the parentheses or the port number shown here:
• bootpc (port 68)
• bootps (port 67)
• discard (port 9)
• dns (port 53)
• dnsix (port 90)
• echo (port 7)
• mobile-ip (port 434)
• netbios-dgm (port 138)
• netbios-ns (port 137)
• ntp (port 123)
• tacacs (port 65)
• talk (port 517)
• time (port 37)
• tftp (port 69)
Conguring IP parameters - Layer 3 switches
FastIron Ethernet Switch Layer 3 Routing
53-1003627-04 81