DHCP

[Olliedawg]

If I try to reconcile the DHCP scope on my main DHCP server(Server1), I get these two IP addresses showing, which are not in my address pool..If I press Reconcile, they disappear. If I press Verify again when the window refreshes, the addresses pop back up!

I have checked the DHCP logs from the past few days, I can't even see a trace of these IP addresses. These IP's are not listed in the Address Lease tab

 

Only thing I can think of which has caused this, is last Friday we had some Server problems where the main DC sits, so DHCP/DNS will have failed over to the backup DC (Server2). Something seems to have gone a miss here. I have checked & the DHCP config seems to be exactly the same between the main DHCP (Server1) and the failover (Server2).

Another thing I have noticed since then, is strange latency spikes when pinging certain switches on the LAN .. does this sound like symptoms of a possible IP conflict due to DHCP? I've not had the chance to try to isolate the issue as exams are on and I don't want to cause any disturbance.

 

Example of latency when pinging one of the switches

 

 

Server1 (Main DC, Main DHCP, Main DNS)

Server2 (Second DC, Hot Standby DHCP, Failover DNS)

[Davit2005]

To me that level of latency does not look too bad. Are your switches static or dhcp IP assigned?

 

Do you have a core switch with intervlan routing or is all the routing been done at the router/firewall?

 

Also the IP addresses, do they have same MAC address?

Edited May 3, 2024 by Davit2005

[Olliedawg]

To me that level of latency does not look too bad. Are your switches static or dhcp IP assigned?

 

Do you have a core switch with intervlan routing or is all the routing been done at the router/firewall?

 

Also the IP addresses, do they have same MAC address?

 

Switches are all static

 

VLAN's done at firewall

 

I cant see the IP addresses as being online as of yet (from a ping test), will have to do more digging

[Olliedawg]

Update : A lot better now!

 

I believe it was Senso Client that was causing the issues. I have just caught up with this : senso.cloud | Service Status (freshstatus.io) Seems like a module update causes some unexpected issues for a lot of users.

 

Still no further on with the two addresses which I cannot Reconcile, probably need to recreate dhcp database to solve that one.