DHCP & PXE boot workstations

[Simon Hobson]

DOYLE FOSTER wrote:

>Mar 15 15:17:07 spprlyfi10 dhcpd: DHCPDISCOVER from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:08 spprlyfi10 dhcpd: DHCPOFFER on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:12 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.171 (172.19.34.253) from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:12 spprlyfi10 dhcpd: DHCPACK on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:12 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.171 from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:12 spprlyfi10 dhcpd: DHCPACK on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:27 spprlyfi10 dhcpd: DHCPDISCOVER from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:27 spprlyfi10 dhcpd: DHCPOFFER on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1

That looks normal

>Mar 15 15:17:31 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.221 (172.19.34.254) from 00:19:b9:02:06:8f via 172.23.255.1: lease owned by peer
>Mar 15 15:17:31 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.221 from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:17:31 spprlyfi10 dhcpd: DHCPACK on 172.23.255.221 to 00:19:b9:02:06:8f via 172.23.255.1

Now that's interesting. The CLIENT has requested a different address and as it's available it's been acked. I see also that failover is in use here, are you sure that both servers are fully in sync ?

>Mar 15 15:18:05 spprlyfi10 dhcpd: DHCPDISCOVER from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:18:05 spprlyfi10 dhcpd: DHCPOFFER on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:22 spprlyfi10 dhcpd: DHCPDISCOVER from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:23 spprlyfi10 dhcpd: DHCPOFFER on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:27 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.171 (172.19.34.253) from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:27 spprlyfi10 dhcpd: DHCPACK on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:27 spprlyfi10 dhcpd: DHCPREQUEST for 172.23.255.171 from 00:19:b9:02:06:8f via 172.23.255.1
>Mar 15 15:33:27 spprlyfi10 dhcpd: DHCPACK on 172.23.255.171 to 00:19:b9:02:06:8f via 172.23.255.1

And again the client has done a discover and been offered the last address this server gave it.

My guess, and bear in mind that I'm not familiar with failover, is that the two servers have handed out different leases to this client in the past. When the client does a dhcp discover it gets two different offers and it is random which one it takes (normally the first one it receives which depends on a number of factors including server and network load).