Extreme Networks ExtremeWare XOS 11.3, Manual

Page: 511 / 698

UDP Forwarding
ExtremeWare XOS 11.3 Concepts Guide
511
This command displays the configuration of the BOOTP relay service and the addresses that are
currently configured.
UDP Forwarding
UDP Forwarding is a flexible and generalized routing utility for handling the directed forwarding of
broadcast UDP packets. UDP forwarding enables you to configure your switch so that inbound
broadcast UDP packets on a VLAN are forwarded to a particular destination IP address or VLAN.
UDP Forwarding allows applications, such as multiple DHCP relay services from differing sets of
VLANs, to be directed to different DHCP servers. The following rules apply to UDP broadcast packets
handled by this feature:
●
If the UDP profile includes BOOTP or DHCP, it is handled according to guidelines specified in RFC
1542.
●
If the UDP profile includes other types of traffic, these packets have the IP destination address
modified as configured, and changes are made to the IP and UDP checksums and decrements to the
TTL field, as appropriate.
If UDP Forwarding is used for BOOTP or DHCP forwarding purposes, do not configure or use the
existing
bootprelay
function. However, if the previous
bootprelay
functions are adequate, you may
continue to use them.
NOTE
UDP forwarding only works across a layer 3 boundary and currently, UDP forwarding can be applied to IPv4 packets
only, not to IPv6 packets.
Configuring UDP Forwarding
To configure UDP Forwarding, create an policy file for your UDP profile, and then associate the profile
with a VLAN using the following command:
configure vlan <vlan_name> udp-profile [<profilename> | none]
You can apply a UDP forwarding policy only to an L3 VLAN (a Vlan having at least one IP address
configured on it). If there is no IP address configured on the VLAN, then the command will be rejected.
UDP profiles are similar to ACL policy files. UDP profiles use a subset of the match conditions allowed
for ACLs. A UDP forwarding policy must contain only the following attributes. Unrecognized attributes
will be ignored.
●
Match attributes
■
Destination UDP Port Number (destination-port)
■
Source IP address (source-ipaddress)
●
Action modified (set) attributes
■
Destination IP address (destination-ipaddress)
■
VLAN name (vlan)
Policy files used for UDP forwarding are processed differently from standard policy files. Instead of
terminating when an entry’s match clause becomes true, each entry in the policy file will be processed
and the corresponding action will be taken for each true match clause.