If the link state of a port transitions from up to down, or if an EAPOL-logoff frame is received, the port returns to the unauthorized state. When a client logs off, it sends an EAPOL-logoff message, causing the switch port to transition to the unauthorized state.
Exactly what kind of security restriction are you trying to accomplish? I'm not sure what version of IOS you are using, but there are better options with later version. such as "multi-auth", which requires every PC that connects to that port to authenticate.
Using "multi-host" mode for dot1x authentication on all ports puts a big hole in any security you try to enforce.
I'm testing the Dot1x multi-auth feature of the lastest IOS for the 3750. It works perfectly for two machines that are authorized. Is it possible for the switch allow traffic from an authorized host and deny traffic from a machine that does pass authentication? So far it seems to drop all traffic on the port, as soon as the unathorized machine is connected.
If you are using the latests code (12.2.50) using the "authentication host-mode multi-auth" and the "authentication violation protect" commands should do the trick according to Cisco's 3750 documentation. Which also states a limit of 8 (authenticated) hosts.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...