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DHCP: XID did NOT MATCH in dhcpc_for_us()

anthony.yu
Level 1
Level 1

When I move a laptop from one vlan to another vlan. My WindowsXP Pro laptop shows me a limited connectivity. I have to use ipconfig /release and /renew in command prompt manually to resolve it.

That's why I enabled the debug command -

debug dhcp detail and debug ip dhcp server events on the Cat4506 where the DHCP server locates.

I saw the debug messages on the console:

May 9 16:13:21.690 EST: DHCP: XID did NOT MATCH in dhcpc_for_us()

May 9 16:13:21.690 EST: DHCPD: forwarding BOOTREPLY to client 0011.2532.9f08.

May 9 16:13:21.690 EST: DHCPD: Forwarding reply on numbered intf

May 9 16:13:21.690 EST: DHCPD: broadcasting BOOTREPLY to client 0011.2532.9f08.

May 9 16:13:21.690 EST: DHCP: Received a BOOTREP pkt Not for us..: xid: 0x2869

F8EE

May 9 16:13:30.694 EST: DHCP: XID did NOT MATCH in dhcpc_for_us()

May 9 16:13:30.694 EST: DHCPD: forwarding BOOTREPLY to client 0011.2532.9f08.

May 9 16:13:30.694 EST: DHCPD: Forwarding reply on numbered intf

May 9 16:13:30.694 EST: DHCPD: broadcasting BOOTREPLY to client 0011.2532.9f08.

May 9 16:13:30.694 EST: DHCP: Received a BOOTREP pkt Not for us..: xid: 0x2869

F8EE

2 Replies 2

wong34539
Level 6
Level 6

"The 'xid' field is used by the client to match incoming DHCP messages with pending request. A DHCP client MUST choose 'xid's in such a way as to minimize the chance of using an 'xid' identical to one used by another client. For example, a client may choose a different, random initial 'xid' each time the client is rebooted, and subsequently use sequential 'xid's until the next reboot."

How do I fix this mismatch?

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