802.1x 客户端获取ip过程 很详细

客户端关联---802.1x认证--dhcp获取ip过程，debug详细过程

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Overview:

In this post we’ll examine a case where the client is unable to join the WLAN as the DHCP server continuously offered it an IP address that was already in use on the network. The client was then excluded for a period of time due to IP theft/reuse. When clients are excluded it can actually be quite helpful as the WLC will list a reason for the exclusion, possible conditions are:

Excessive 802.11 Association Failures

Excessive 802.11 Authentication Failures

Excessive 802.1X Authentication Failures

IP Theft or IP Reuse

Excessive Web Authentication Failures

Debug using CLI:

Client associated

802.1x completed successfully

DHCP discover sent by client

WLC relays DHCP discover to 1.2.3.4

DHCP server provides an offer (4.3.2.1)

Client Requests 4.3.2.1 from DHCP server

DHCP server accepts request

WLC recognises that the requested IP is already in use (assigned to a virtual interface)

Not shown – client is excluded due to IP theft/reuse

Association received

dot1x - moving mobile xx:xx:xx:xx:xx:xx into Connecting state

EAP State update from Connecting to Authenticating for mobile xx:xx:xx:xx:xx:xx

Processing Access-Accept for mobile xx:xx:xx:xx:xx:xx

Received Auth Success while in Authenticating state for mobile xx:xx:xx:xx:xx:xx

0.0.0.0 8021X_REQD (3) Change state to L2AUTHCOMPLETE (4) last state 8021X_REQD (3)

0.0.0.0 L2AUTHCOMPLETE (4) Change state to DHCP_REQD (7) last state L2AUTHCOMPLETE (4)

DHCP received op BOOTREQUEST (1) (len 317,vlan 99, port 13, encap 0xec03)

DHCP transmitting DHCP DISCOVER (1)

DHCP transmitting DHCP OFFER (2)

DHCP sending REQUEST to 1.2.3.4 (len 358, port 13, vlan 32)

DHCP received op BOOTREPLY (2) (len 312,vlan 32, port 13, encap 0xec00)

DHCP failed to register IP 4.3.2.1 - dropping ACK