This VCDX exam note will be short and sweet. The networking section has a lot of repeated lessons (which is good 
). The main takeaways for me in this section are:
Configure Advanced Service Console Networking: Redundant HA Heartbeat
- There are two heartbeats that occur. Inter-node and network connectivity (Service Console default gateway by default).
- Inter-node heartbeat occurs every 5 seconds by default
- Network connectivity (read isolation response) heartbeat occurs every 15 seconds by default.
- Redundant networking for HA can occur with NIC teams, a second service console, or both.
- Advanced HA options for redundancy include:
das.isolationaddress(Used to set another isolation heartbeat address. You can have up to 10 usingdas.isolationaddressX- where X is a number 1-10)das.usedefaultisolationaddress(Value is true or false. Determines if the default isolation address of the Service Console’s default gateway should be used.)das.failuredetectiontime(The timeout for the host (15000 milliseconds by default) to declare another host dead when receiving no heartbeats).das.failuredetectioninterval(Changes the inter-node heartbeat interval)
Configure Hostname Resolution
- Three files
/etc/hosts/etc/nsswitch.conf(Look for the “hosts: files dns” entry. This determines the order of name resolution. Files then DNS)./etc/resolv.conf(Nameservers and search suffix are listed in this file).