Cisco NAC3350-PROF-K9 - NAC Profiler Server Installation Manual page 141

Chapter 4 Configuring High Availability (HA)
Figure 4-10
Note If a CAS was previously configured and added to the CAM as a standalone CAS, it must be deleted prior
to configuring it for HA. After HA configuration is complete on both CASs, the Service IP is then
entered in the New Server form to add the HA-CAS pair to the CAM.
To ensure heartbeat redundancy, Cisco recommends configuring optional Heartbeat UDP Interface 2 or
Note
3 between the HA CASs in your deployment.
Failover Events
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Note
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OL-20326-01
Active CAS in an HA-Pair
If multiple heartbeat UDP interfaces are configured, then they must all fail for the standby system
to take over. See Physical Connection, page 4-22
If the CAS is unable to communicate with the CAM:
Users that are already connected will not be affected.
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New users will not be able to log in.
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You can configure link-based failover. Two IP addresses that are external to the CAS are configured
for Link-detect: one on the trusted network, the other on the untrusted network.
The active and standby CAS will send ICMP ping packets via eth0 to the IP address on the
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trusted network.
The active and standby CAS will send ICMP ping packets via eth1 to the IP address on the
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untrusted network.
If your network topology restricts Link-detect functionality between your CAS HA pair
appliances, you can also use the /etc/ha.d/linkdetect.conf file to enforce Link-detect behavior
on your eth0 and/or eth1 interfaces. See
The status of these ping packets is communicated between the CASs via the heartbeat signal:
If the active and standby CAS can ping both external IPs, no failover occurs
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If the active and standby CAS cannot ping either of the external IPs, no failover occurs
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If the active CAS cannot ping either of the external IPs, but the standby CAS can ping them,
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failover occurs
Both the Clean Access Manager and Clean Access Server are designed to automatically reboot in
the event of a hard-drive failure, thus automatically initiating failover to the standby CAM/CAS.
Installing a Clean Access Server High Availability Pair
for additional details.
Link-Detect Interfaces, page 4-45
Cisco NAC Appliance Hardware Installation Guide
for more details.
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