bus/slot/port of the interface. The Cluster ID must be unique for each cluster in a network.
As the shared IP address always has the same hardware address, there will be no latency time in
updating ARP caches of units attached to the same LAN as the cluster when failover occurs.
When a cluster member discovers that its peer is not operational, it broadcasts gratuitous ARP
queries on all interfaces using the shared hardware address as the sender address. This allows
switches to re-learn within milliseconds where to send packets destined for the shared address. The
only delay in failover therefore, is detecting that the active unit is down.
ARP queries are also broadcast periodically to ensure that switches do not forget where to send
packets destined for the shared hardware address.
HA with Anti-Virus and IDP
If a NetDefendOS cluster has the Anti-Virus or IDP subsystems enabled then updates to the
Anti-Virus signature database or IDP pattern database will routinely occur. These updates involve
downloads from the external D-Link databases and they require NetDefendOS reconfiguration to
occur for the new database contents to become active.
A database update causes the following sequence of events to occur in an HA cluster:
1.
The active (master) unit downloads the new database files from the D-Link servers. The
download is done via the shared IP address of the cluster.
2.
The active (master) node sends the new database files to the inactive peer.
3.
The inactive (slave) unit reconfigures to activate the new database files.
4.
The active (master) unit now reconfigures to activate the new database files causing a failover
to the slave unit. The slave is now the active unit.
5.
After reconfiguration of the master is complete, failover occurs again so that the master once
again becomes the active unit.
11.2. HA Mechanisms
Chapter 11. High Availability
412
Summary of Contents for 800 - DFL 800 - Security Appliance
Page 24: ...1 3 NetDefendOS State Engine Packet Flow Chapter 1 NetDefendOS Overview 24 ...
Page 69: ...2 6 4 Restore to Factory Defaults Chapter 2 Management and Maintenance 69 ...
Page 121: ...3 9 DNS Chapter 3 Fundamentals 121 ...
Page 181: ...4 7 5 Advanced Settings for Transparent Mode Chapter 4 Routing 181 ...
Page 192: ...5 5 IP Pools Chapter 5 DHCP Services 192 ...
Page 282: ...6 7 Blacklisting Hosts and Networks Chapter 6 Security Mechanisms 282 ...
Page 300: ...mechanism 7 3 7 SAT and FwdFast Rules Chapter 7 Address Translation 300 ...
Page 301: ...7 3 7 SAT and FwdFast Rules Chapter 7 Address Translation 301 ...
Page 318: ...8 3 Customizing HTML Pages Chapter 8 User Authentication 318 ...
Page 322: ...ALG 9 1 5 The TLS Alternative for VPN Chapter 9 VPN 322 ...
Page 377: ...Management Interface Failure with VPN Chapter 9 VPN 377 ...
Page 408: ...10 4 6 SLB_SAT Rules Chapter 10 Traffic Management 408 ...
Page 419: ...11 5 HA Advanced Settings Chapter 11 High Availability 419 ...
Page 426: ...12 3 5 Limitations Chapter 12 ZoneDefense 426 ...
Page 449: ...13 9 Miscellaneous Settings Chapter 13 Advanced Settings 449 ...