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Not able to grab IP from Core Switch


I have 3 switches, 1 set to core switches with dhcp server and all vlan, the other 2 switches are connected to this core switch via trunk and get all the vlan from the core switch, vlan as below


Core SW - VLAN 11, VLAN 13, VLAN  21 and VLAN 888

SW1 - VLAN 13 and VLAN 888

SW2 - VLAN 13 and VLAN 888


my issue is that SW 1 is able to grab VLAN 11 DHCP from Core SW but not SW2

VLAN13 is configure to remote manage this switches

Trunk port only allow VLAN 11, VLAN 13, VLAN 21 and VLAN 888


When I do sh vlan, SW1 and SW2 are able to list all the above VLAN



What switches do you have?  You may want to look at your DHCP relay or IP helper settings.

SG500, dhcp server on the core sw, never set any dhcp relay on SW1


I assume you mean that  you configured DHCP server scopes for  all the VLANs on the core switch.  Since you are getting the address via SW1 but not SW2 we know that the DHCP-server is accessible via that VLAN and that your VLAN interface is up. It sounds like you are explicitly setting the allowed vlans on the trunk.  Typically I find this to be a simple mistake where you allowed the VLAN on one side of the trunk, but didn't allow it on the other side.

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I have check on CSW and SW2, both trunk have all the VLAN 11, VLAN 13, VLAN 21 and VLAN 888


Is your default VLAN the same on all the switches?


Were they setup using the same firmware version?  Maybe start from factory reset?

OK.  Next thing to try is plug a couple of devices in VLAN 11 into both the CSW and SW2 and give them static addresses.  Can they ping each other?  If that works there is something more complicated going on. 

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I found this in release notes for firmware  There was a DHCP problem in prior versions.


my Firmware version is, so should not hit the DHCP issue

I cannot see the port on the GUI being lighted up when a PC is being plug to a port but on physical sw, the port is lighted up.

Try rebooted also the same issue

I put static IP which i cannot ping to the gateway, does that mean is the switch faulty?

Not necessarily. Did you put another device, not just the gateway on in that same VLAN on the core switch? How about if you put two static IP'd devices on switch 2 ca they ping each other?

Enable SSH and show the output of 'show switchport <interface to other switch>' on each swtich

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cant ping even on the same sw

OK.  Disconnect it from the Core switch factory reset it, re-configure the VLAN and ports and then test again.  IF that fails its definitely a defective switch.   

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