Catalyst 6500 become L3 after reboot

Unanswered Question
Feb 22nd, 2009

Hello All,

We have Catalyst 6500 SUP-720-3B( Dual SUP ) IOS ver :12.2(33)SXH2a .

Normally working in L2 mode after reboot the Switch comes up in L3 mode. No ip routing resolves this problem till the next reboot. (The configuration has been saved in Startup-Config ).

Did someone experienced issue likes this?

I have this problem too.
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glen.grant Sun, 02/22/2009 - 13:03

You cannot set the device as a strict layer 2 device in a sup 720 , routing is on by default even if it takes that command . The only difference in the way it works would be the management of the switch instead of using a default gateway as you would in say a 2960 you have to use a default static route . Unless you turn on routed ports and or created layer 3 SVI's it is basically running as a layer 2 switch .

y-asulin Sun, 02/22/2009 - 21:07

Do you means that no ip routing command isn't affect in a Sup 720 ?

vishwancc Sun, 02/22/2009 - 21:18


By default all the ports on the L3 ports (Routed) if you give show interface status you could see that.

To change that you have to change it to L2 using switchport command.



Giuseppe Larosa Mon, 02/23/2009 - 02:45

Hello Yossi,

we have same HW and SW but we use it as L3 device.

However, a possible workaround can be to emulate a L2 switch

instead of

no ip routing

ip default-gateway gw-ip-addr

you can use

ip routing

ip route gw-ip-addr

then it is enough to skip to define SVIs for all the Vlans in use and your device will act as a L2 switch as desired.

Hope to help



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