HP MSR2000 Configuration Manual page 348

Analysis
When the access device detects that the client IP address is changed, it sends an unsolicited portal
packet to notify of the IP change to the portal authentication server. The portal authentication server
notifies of the authentication success only after it receives the IP change notification from both the access
device and the client.
If the BAS-IP or BAS-IPv6 address carried in the portal notification packet is different from the portal
device IP address specified on the portal authentication server, the portal authentication server discards
the portal notification packet. As a result, the portal authentication server regards the user has failed the
authentication.
Solution
Configure the BAS-IP or BAS-IPv6 attribute on the interface enabled with portal authentication. Make
sure the attribute value is the same as the portal device IP address specified on the portal authentication
server.
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