WLC2125 DHCP problem

Boris Simunko — Sun, 04 Jul 2021 03:14:41 GMT

hello!

the wifi clients can not get an address through the wlc.

the dhcp server is external, and there are no problems for wired clients in the same vlan.

debug message

(Cisco Controller) >debug dhcp packet enable

(Cisco Controller) >*DHCP Socket Task: May 25 14:46:22.506: a0:88:b4:25:64:60 DHCP received op BOOTREQUEST (1) (len 308,vlan 0, port 7, encap 0xec03)

*DHCP Socket Task: May 25 14:46:22.506: a0:88:b4:25:64:60 DHCP selecting relay 1 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:22.506: a0:88:b4:25:64:60 DHCP selected relay 1 - 192.168.119.10 (local address 192.168.30.2, gateway 192.168.30.1, VLAN 30, port 1)

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP transmitting DHCP DISCOVER (1)

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP xid: 0x379889ec (932743660), secs: 0, flags: 80

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP chaddr: a0:88:b4:25:64:60

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP ciaddr: 0.0.0.0, yiaddr: 0.0.0.0

*DHCP Socket Task: May 25 14:46:22.507: a0:88:b4:25:64:60 DHCP siaddr: 0.0.0.0, giaddr: 192.168.30.2

*DHCP Socket Task: May 25 14:46:22.508: a0:88:b4:25:64:60 DHCP sending REQUEST to 192.168.30.1 (len 350, port 1, vlan 30)

*DHCP Socket Task: May 25 14:46:22.508: a0:88:b4:25:64:60 DHCP selecting relay 2 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:22.508: a0:88:b4:25:64:60 DHCP selected relay 2 - NONE

*apfOrphanSocketTask: May 25 14:46:23.908: a0:88:b4:25:64:60 Invalid MSCB state: ipAddr=169.254.210.31, regType=2, Dhcp required!

*DHCP Socket Task: May 25 14:46:25.504: a0:88:b4:25:64:60 DHCP received op BOOTREQUEST (1) (len 308,vlan 0, port 7, encap 0xec03)

*DHCP Socket Task: May 25 14:46:25.505: a0:88:b4:25:64:60 DHCP selecting relay 1 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:25.505: a0:88:b4:25:64:60 DHCP selected relay 1 - 192.168.119.10 (local address 192.168.30.2, gateway 192.168.30.1, VLAN 30, port 1)

*DHCP Socket Task: May 25 14:46:25.505: a0:88:b4:25:64:60 DHCP transmitting DHCP DISCOVER (1)

*DHCP Socket Task: May 25 14:46:25.505: a0:88:b4:25:64:60 DHCP op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1

*DHCP Socket Task: May 25 14:46:25.505: a0:88:b4:25:64:60 DHCP xid: 0x379889ec (932743660), secs: 3, flags: 80

*DHCP Socket Task: May 25 14:46:25.506: a0:88:b4:25:64:60 DHCP chaddr: a0:88:b4:25:64:60

*DHCP Socket Task: May 25 14:46:25.506: a0:88:b4:25:64:60 DHCP ciaddr: 0.0.0.0, yiaddr: 0.0.0.0

*DHCP Socket Task: May 25 14:46:25.506: a0:88:b4:25:64:60 DHCP siaddr: 0.0.0.0, giaddr: 192.168.30.2

*DHCP Socket Task: May 25 14:46:25.506: a0:88:b4:25:64:60 DHCP sending REQUEST to 192.168.30.1 (len 350, port 1, vlan 30)

*DHCP Socket Task: May 25 14:46:25.506: a0:88:b4:25:64:60 DHCP selecting relay 2 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:25.507: a0:88:b4:25:64:60 DHCP selected relay 2 - NONE

*DHCP Socket Task: May 25 14:46:33.811: a0:88:b4:25:64:60 DHCP received op BOOTREQUEST (1) (len 308,vlan 0, port 7, encap 0xec03)

*DHCP Socket Task: May 25 14:46:33.811: a0:88:b4:25:64:60 DHCP selecting relay 1 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:33.811: a0:88:b4:25:64:60 DHCP selected relay 1 - 192.168.119.10 (local address 192.168.30.2, gateway 192.168.30.1, VLAN 30, port 1)

*DHCP Socket Task: May 25 14:46:33.811: a0:88:b4:25:64:60 DHCP transmitting DHCP DISCOVER (1)

*DHCP Socket Task: May 25 14:46:33.811: a0:88:b4:25:64:60 DHCP op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1

*DHCP Socket Task: May 25 14:46:33.812: a0:88:b4:25:64:60 DHCP xid: 0x379889ec (932743660), secs: 11, flags: 80

*DHCP Socket Task: May 25 14:46:33.812: a0:88:b4:25:64:60 DHCP chaddr: a0:88:b4:25:64:60

*DHCP Socket Task: May 25 14:46:33.812: a0:88:b4:25:64:60 DHCP ciaddr: 0.0.0.0, yiaddr: 0.0.0.0

*DHCP Socket Task: May 25 14:46:33.812: a0:88:b4:25:64:60 DHCP siaddr: 0.0.0.0, giaddr: 192.168.30.2

*DHCP Socket Task: May 25 14:46:33.812: a0:88:b4:25:64:60 DHCP sending REQUEST to 192.168.30.1 (len 350, port 1, vlan 30)

*DHCP Socket Task: May 25 14:46:33.813: a0:88:b4:25:64:60 DHCP selecting relay 2 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:33.813: a0:88:b4:25:64:60 DHCP selected relay 2 - NONE

*DHCP Socket Task: May 25 14:46:46.488: 98:4b:e1:ed:2d:c0 DHCP received op BOOTREQUEST (1) (len 308,vlan 0, port 1, encap 0xec00)

*DHCP Socket Task: May 25 14:46:46.488: 98:4b:e1:ed:2d:c0 DHCP dropping packet (no mscb) found - (giaddr 0.0.0.0, pktInfo->srcPort 68, op: 'BOOTREQUEST')

*DHCP Socket Task: May 25 14:46:46.488: 98:4b:e1:ed:2d:c0 DHCP received op BOOTREPLY (2) (len 377,vlan 0, port 1, encap 0xec00)

*DHCP Socket Task: May 25 14:46:46.489: 98:4b:e1:ed:2d:c0 DHCP dropping packet (no mscb) found - (giaddr 0.0.0.0, pktInfo->srcPort 67, op: 'BOOTREPLY')

*DHCP Socket Task: May 25 14:46:49.996: a0:88:b4:25:64:60 DHCP received op BOOTREQUEST (1) (len 308,vlan 0, port 7, encap 0xec03)

*DHCP Socket Task: May 25 14:46:49.997: a0:88:b4:25:64:60 DHCP selecting relay 1 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

*DHCP Socket Task: May 25 14:46:49.997: a0:88:b4:25:64:60 DHCP selected relay 1 - 192.168.119.10 (local address 192.168.30.2, gateway 192.168.30.1, VLAN 30, port 1)

*DHCP Socket Task: May 25 14:46:49.997: a0:88:b4:25:64:60 DHCP transmitting DHCP DISCOVER (1)

*DHCP Socket Task: May 25 14:46:49.997: a0:88:b4:25:64:60 DHCP op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1

*DHCP Socket Task: May 25 14:46:49.997: a0:88:b4:25:64:60 DHCP xid: 0x379889ec (932743660), secs: 27, flags: 80

*DHCP Socket Task: May 25 14:46:49.998: a0:88:b4:25:64:60 DHCP chaddr: a0:88:b4:25:64:60

*DHCP Socket Task: May 25 14:46:49.998: a0:88:b4:25:64:60 DHCP ciaddr: 0.0.0.0, yiaddr: 0.0.0.0

*DHCP Socket Task: May 25 14:46:49.998: a0:88:b4:25:64:60 DHCP siaddr: 0.0.0.0, giaddr: 192.168.30.2

*DHCP Socket Task: May 25 14:46:49.998: a0:88:b4:25:64:60 DHCP sending REQUEST to 192.168.30.1 (len 350, port 1, vlan 30)

*DHCP Socket Task: May 25 14:46:49.998: a0:88:b4:25:64:60 DHCP selecting relay 2 - control block settings:

dhcpServer: 0.0.0.0, dhcpNetmask: 0.0.0.0,

dhcpGateway: 0.0.0.0, dhcpRelay: 192.168.30.2 VLAN: 30

Re: WLC2125 DHCP problem

weterry — Thu, 26 May 2011 05:36:48 GMT

Please provide a "debug client " instead of the dhcp debug...

The provided debug shows the client sents dhcp discover several times with no response, but then it shows we finally get a response. However, we dont have an MSCB state for the client, meaning we must have removed him by that time but since you dont have a client debug we can't confirm that...

Anyhow, the fact that we see a boot reply like 15 seconds after the requests, make me think you dhcp server does not like our dhcp proxy.

My suggestion would be for you to disable dhcp proxy "config dhcp proxy disable"

However, if you do this, you need to make sure your infrastructure is configured approriately to get a DHCP broadcast to the dhcp server (typically ip helper-address, or a dhcp server in all vlans...)

Either way, it seems suspicious that we suddenly get a boot reply long after we last sent a bootrequest to the dhcp server....

-Wesley Terry

Thank you for this post.

_NATALIE_ — Sat, 13 Dec 2014 15:42:54 GMT

Thank you for this post. Wesley - your suggestions saved me from extended troubleshooting efforts after a DHCP server replacement that interrupted DHCP services on the WiFi. The new server didn't play well with the DHCP proxy. Cheers to you!

topic Re: WLC2125 DHCP problem in Wireless

WLC2125 DHCP problem

Re: WLC2125 DHCP problem

Thank you for this post.