802.1x NON compatible clients time out on EAPOL requests after about a minute. Swich then opens the port for use but DHCP has already timed out meaning a manual ipconfig /renew.
802.1x Compatible Clients that are domain members - works fine and go to either 20 or 50 depending on the NPS/healthcheck outcome. 802.1x Compatible Clients that are not domain members go to guest VLAN by the swtich, as it's an access-reject reply from the RADIUS server, the DHCP doesn't time out early...
All clients that are 802.1x compatible are Vista.
Non 802.1x clients are guest machines - I cannot change the settings, DHCP registry settings etc at all on these. They range from Vista to XP and possibly Linux.
DHCP is purely a client initiated protocol. There is nothing on the switch or elsewhere in your network that can be used to initiate a client IP renewal. For Windows XP and Vista, when the initial DHCP requests time out, we assign the computer an address in the 169.254.x.x (APIPA address) range. However, the client will continue to send out DHCP discovers every three minutes for as long as the connection is up. I can't speak for how a linux or mac client would behave, but i suspect it would be similar.Clay Seymour - MSFT
