Forward UDP broadcast packets in Catalyst 3850

[gciotto]

Hello,

I'm specifying a new model for the access switches in our lab. One of applications uses a protocol which sends UDP broadcasts in a specific port to retrieve information from the hosts present in the subnet. As we'll have many VLANs and many subnets consequently, we want to forward these broadcast packets between two (or more) subnets (we're specifying a Nexus L3 switch as well). I've tried to search this feature in the Catalyst 3850's OS, Cisco IOS XE, but I was unsuccessful in determining if this switch does or doesn't have a version of ip forward-protocol implemented.

Could you clarify this point, please? If yes, is this feature available even in the LAN Base license?

Gustavo

[Mark Malone]

Hi
ios-xe has a command called ip directed-broadcast under the ip interface available would that work for you ? I only see ip forward udp under the global command string , this is on a standard 3850 , it ipbase not lanbase and its on ipservices too

cisco WS-C3850-24T (MIPS)

(config-if)#ip directed-broadcast ?
<1-199> A standard IP access list number
<1300-2699> A standard IP expanded access list number
<cr>

(config)#ip forward-protocol udp ?
<0-65535> Port number
biff Biff (mail notification, comsat, 512)
bootpc Bootstrap Protocol (BOOTP) client (68)
bootps Bootstrap Protocol (BOOTP) server (67)
discard Discard (9)
dnsix DNSIX security protocol auditing (195)
domain Domain Name Service (DNS, 53)
echo Echo (7)
isakmp Internet Security Association and Key Management Protocol (500)
mobile-ip Mobile IP registration (434)
nameserver IEN116 name service (obsolete, 42)
netbios-dgm NetBios datagram service (138)
netbios-ns NetBios name service (137)
netbios-ss NetBios session service (139)
non500-isakmp Internet Security Association and Key Management Protocol (4500)
ntp Network Time Protocol (123)
pim-auto-rp PIM Auto-RP (496)
rip Routing Information Protocol (router, in.routed, 520)
snmp Simple Network Management Protocol (161)
snmptrap SNMP Traps (162)
sunrpc Sun Remote Procedure Call (111)
syslog System Logger (514)
tacacs TAC Access Control System (49)
talk Talk (517)
tftp Trivial File Transfer Protocol (69)
time Time (37)
who Who service (rwho, 513)
xdmcp X Display Manager Control Protocol (177)
<cr>

[gciotto]

Hello Mark,

Thanks for your answer! We could use ip directed-broadcast, but in this case a configuration would be needed in the hosts. This solution we are avoiding at this moment.

The ideal solution for us is ip forward-protocol. Have you used a switch licensed with IP base to generate those outputs?

Gustavo

[Mark Malone · Accepted solution]

I checked ipbase an ipservices, I have multiple 3850s globally , both commands seem to be on both switches just found a lanbase didn't think I had any :)
(config)#do sh license right-to-use
Slot# License name Type Count Period left
----------------------------------------------------------
1 lanbase permanent N/A Lifetime

License Level on Reboot: lanbase


(config)#ip for
(config)#ip forward-protocol ?
nd Sun's Network Disk protocol
sdns Network Security Protocol
spanning-tree Use transparent bridging to flood UDP broadcasts
turbo-flood Fast flooding of UDP broadcasts
udp Packets to a specific UDP port

(config)#ip forward-protocol