Last week we had a power outage. When power came back, our HP switches came back online but with a problem. A few VLANs in our HP 5406 switches did not get an IP address from DHCP server, the other VLAN on the same switch can get the IP address from DHCP server.

Our HP switches are connected to Cisco 3750 Layer 3 switch which is connected to ASA and to Internet. I did everything to check whether the problem could be in DHCP server. I also checked the switches configurations with spanning tree configs as well but nothing changed the situation.

After spending a lot of time on troubleshooting I created new VLANs on that trouble maker switches and assigned the ports on that VLANs as an untagged and it started working again. Still I don't understand what was the problem. I am wondering that if we again face the power outage issue than this problem might be repeat again.

Can somebody help me identify the root cause of the issue?

The Firmware we are using on that switches are: K.15.13.0005

  • The Best Practice(tm) is to use static addresses on infrastructure devices. These devices need to be fully functional before any services are online. – Ricky Aug 21 '15 at 19:49
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    Have you tried dhcp restart? I've seen simillar situations and in 3/4 it was no free leases. – Paweł Borowski Aug 25 '15 at 9:40

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