lost connection to switch

Unanswered Question
Sep 25th, 2011
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I created several vlans in a 2950 switch. I set vlan1 as with an ip address and I was able to remotely connect to the switch when I added an ip address to vlan 10 and enabled it, I suddenly lost connection to the switch.  Note that I added ports 1-3 to vlan 10 and there is nothing plugged into these ports now. Any ideas as to why I lost connection when I added that ip address.

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Richard Burts Sun, 09/25/2011 - 19:55
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The 2950 is a layer 2 switch and as such it can support only a single active VLAN interface. When VLAN 1 was the only active VLAN interface it was fine and you had connectivity. But when you added interface vlan 10 then the switch shut down interface vlan 1. And then you lost connectivity.

If you have console access to the switch you can remove interface vlan 10 and this will fix the problem. Or you could power cycle the switch. This would remove interface vlan 10. But depending on the last time that you did a copy running start (or a write mem) it could also remove interface vlan1.

Note that the 2950 can have multiple active VLANs. But it can have only a single VLAN interface. Be aware of the difference between a VLAN (which is a layer 2 thing and multiple VLANs are supported) and a vlan interface (which is a layer 3 thing and only a single vlan interface is supported on the 2950).



Joli Martinez Mon, 09/26/2011 - 06:27
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OK.  Then I have an 871 router can I add multiple ip addresses to the 4 port switch and connect that to each vlan?

I want to put my servers on vlan 10, my workstations on vlan20, and have misc computers on vlan30 for testing purpose.  Also I would like all vlans to connect the internet.  Can this be accomplished with only a 2950 and an 871 router?


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