Connection Problem Switch

[RobinD]

Hello guys

My Name is Robin and I am new in this forum. I am a system administrator and i am not that fit on networking right now.

My problem is, that i created a new vlan and i don't get an ip adress (only APIPA) for my device that is connected to the port. For sure the port is right patched. To my infrastructure: I have a stacked SG500X (4x) which is connected to a SG500X in the basement floor, which is connected to a stacked Catalyst 3750 (2x). The catalyst is connected to the Firewall. Then there is a DHCP Server in our network, which usually distributes 192.168.200.X /24 addresses. In my new created VLAN I like to get a 192.168.235.X /24 IP Adress. I created a new DHCP Scope on the DHCP server for that subnet. On every of these three switches I added the vlan on the trunking port. Does anyone come up with a solution?

Thanks in advance.

Robin

[David Harper · Accepted solution]

Is the firewall doing the routing between the VLANs, or is that being done by one of the switches?  Either way, if the DHCP server is on the original VLAN, you will need some additional configuration on the device that is doing to the routing to forward DHCP requests from the new VLAN to the DHCP server.

If the Catalyst switch is doing the routing, then you will need something like 'ip helper-address <dhcp server address>' configured on the VLAN interface for the new VLAN.  If routing is being done by one of the 500X switches, then go to the IP Configuration > DHCP Snooping/Relay section of the GUI.  If the firewall is doing the routing, then obviously the configuration will depend on what type of firewall it is.

Hope that helps a bit.

Cheers,

Dave.

[RobinD]

Hi Dave,
thanks for your answer. I have forgot to add the vlan on the port-channeling, that was the problem. Greetings from switzerland.
Robin