Changes between Initial Version and Version 2 of Ticket #13785

Ticket #13785 – Description

-              initial
+              v2
 Running dhclient -v eth2 shows the guest is declining the IP offer when it fails:
+{{{
 [root@localhost ~]# dhclient -v eth2
 Internet Systems Consortium DHCP Client 4.1.1-P1
 …
 DHCPACK from 192.168.0.1 (xid=0x2bc89bf5)
 DHCPDECLINE on eth2 to 255.255.255.255 port 67 (xid=0x2bc89bf5)
+}}}
 This seems to be because it sees the IP as already existing - though it doesn't. I modified /sbin/dhclient-script to show the arping output like this:
+{{{
         arping -D -c2 -I ${interface} ${new_ip_address}
         RC=$?
         echo "Exit: $RC"
         [ $RC -ne 0 ] && exit_with_hooks 1
+}}}
 Interestingly, if I didn't exit and let it run its own arping afterwards - it would always succeed. More on that shortly.
 Output is below:
+{{{
 [root@localhost ~]# dhclient -v eth2
 Internet Systems Consortium DHCP Client 4.1.1-P1
 …
 Exit: 1
 DHCPDECLINE on eth2 to 255.255.255.255 port 67 (xid=0x2bc89bf5)
+}}}
 Arping detects a broadcast request coming from the IP it just allocated... the Mac address there is the HOST's MAC address. So something on the host sends this request from the allocated IP, and arping here catches it and fails duplicate address detection, meaning dhclient declines the address.