Improve Resiliency
DNS and DHCP service reliability is key to enabling a solid foundation for network services and applications. Discover the techniques that can be used to achieve rock solid core network services.
DNS High-Availability
Implementing DNS-HA involves deploying two appliances in a high-availability pair. Both appliances have their own physical IP addresses, but a virtual IP address (VIP) is shared between them. A heartbeat occurs between the two appliances and they negotiate which one should take control of the VIP. Client systems should be configured to use the VIP for all DNS queries and if the system currently in control of the VIP fails, the second system will take control within 1 second, resulting in no down time as far as the DNS service is concerned.
DNS Anycast
Anycast enables multiple DNS servers to advertise the same destination IP address to the network so that DNS queries are routed to the nearest available DNS server based on the most efficient routing path. If the “closest” DNS server is offline, the network routing topology re-converges and DNS clients are routed to the next closest DNS server, thus providing a resilient DNS service. This is an ideal solution when there are multiple geographically dispersed servers and enables all DNS clients to be configured with consistent DNS server IP addresses.
DHCP Failover
DHCP Failover enables multiple DHCP servers to share the same address ranges in order to provide both load balancing and failover. DHCP Failover can operate in pairs or in a star arrangement with multiple “primary” DHCP servers backed up by a single “failover” server.
Routers will forward DHCP requests to both DHCP servers but only one will respond based on the availability and load balancing algorithms of each server. If one of the servers in the relationship fails, the other server will detect this and begin renewing addresses for existing clients or issuing new leases from the other server’s allocated address pool.
Network link resilience
Dual network ports can be used to provide network link resilience. Each port can be connected to the same or different switches, and if one network link fails, all traffic will automatically fail over to the redundant link.
Next Steps
Getting started with DNS & DHCP reliability is simple. No matter what stage in the process you are at, Calleva Networks can enable you with the resources you need to help Evaluate, Design and Deploy your Core Services infrastructure.
Evaluate: Take our product portfolio for a test drive.
Design: We will create a design overview so you can assess the deployment choices.
