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Broadcast address on a WS-C2980G-A Switch

sabushaban
Level 1
Level 1

In one of our switches,the broadcast address is set up to 10.6.0.0. I Was reading and comparing it to differenent Switches which had the Broadcast 10.1.255.255

Does 10.6.0.0 broadcast on the switch affect the switch ? If so Can I just change it by :

set int sc0 10.6.0.3 255.255.0.0 10.6.255.255 ?

Thanks

Console> (enable) sh int

sl0: flags=50<DOWN,POINTOPOINT,RUNNING>

slip 0.0.0.0 dest 0.0.0.0

sc0: flags=63<UP,BROADCAST,RUNNING>

vlan 1 inet 10.6.0.3 netmask 255.255.0.0 broadcast 10.6.0.0

me1: flags=62<DOWN,BROADCAST,RUNNING>

inet 0.0.0.0 netmask 0.0.0.0 broadcast 0.0.0.0

5 Replies 5

ehoehne
Level 1
Level 1

Seeing 10.6.0.0 listed as the broadcast is very strange. I' ve never seen that with any of our 6509's. 10.6.0.0 is a network address. Anyway, you should be fine if you set it to the correct broadcast address of 10.6.255.255. I hope this helps!

Prashanth Krishnappa
Cisco Employee
Cisco Employee

You might have forrcefully set it this way. Here is a screen capture from my lab 6500

W2-3.17-C6506-A (enable) set int sc0 10.6.0.3 255.255.0.0 10.6.0.0

Interface sc0 IP address, netmask, and broadcast set.

W2-3.17-C6506-A (enable) sh int

sl0: flags=51

slip 0.0.0.0 dest 0.0.0.0

sc0: flags=63

vlan 1 inet 10.6.0.3 netmask 255.255.0.0 broadcast 10.6.0.0

W2-3.17-C6506-A (enable) set int sc0 10.6.0.3 255.255.0.0

Interface sc0 IP address and netmask set.

W2-3.17-C6506-A (enable) sh int

sl0: flags=51

slip 0.0.0.0 dest 0.0.0.0

sc0: flags=63

vlan 1 inet 10.6.0.3 netmask 255.255.0.0 broadcast 10.6.255.255

W2-3.17-C6506-A (enable)

So, Do I need to set the broadcast address or not in the following command? or it learns it automatic ?

int the set int sc0 10.6.0.3 255.255.0.0

The output from my switch for sh int :

Console> (enable) sh int

sl0: flags=50

slip 0.0.0.0 dest 0.0.0.0

sc0: flags=63

vlan 1 inet 10.6.0.3 netmask 255.255.0.0 broadcast 10.6.255.255

me1: flags=62

inet 0.0.0.0 netmask 0.0.0.0 broadcast 0.0.0.0

Thanks

The switch finds the broadcast address based on the subnet mask. You are good to go with "set int sc0 10.6.0.3 255.255.0.0"

glen.grant
VIP Alumni
VIP Alumni

Never seen that before ,someone must have consciously put that in . Normally you don't even have to put that in unless you want a different broadcast address , you just have to set the address and the mask for SC0 and the switch will supply the normal broadcast address for that range .

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