Your network contains an Active Directory domain named contoso.com. The domain contains a main
office and a branch office. An Active Directory site exists for each office. The domain contains two
servers named Server1 and Server2 that run Windows Server 2012 R2.
Both servers have the DHCP Server server role installed. Server1 is located in the main office site.
Server2 is located in the branch office site. Server1 provides IPv4 addresses to the client computers in
the main office site. Server2 provides IPv4 addresses to the client computers in the branch office site.
You need to ensure that if either Server1 or Server2 are offline, the client computers can still obtain IPv4
addresses. The solution must meet the following requirements:
The storage location of the DHCP databases must not be a single point of failure. Server1 must provide
IPv4 addresses to the client computers in the branch office site only if Server2 is offline.
Server2 must provide IPv4 addresses to the client computers in the main office site only if Server1 is
offline.
Which configuration should you use?
A.
Load sharing mode failover partners
B.
Hot standby mode failover partners
C.
A Network Load Balancing (NLB) cluster
D.
A failover cluster
Explanation:
http://blogs.technet.com/b/teamdhcp/archive/2012/06/28/ensuring-high-availability-ofdhcpusingwindowsserver-2012-dhcp-failover.aspx Ensuring
High Availability of DHCP using Windows Server 2012 R2 DHCP Failover The Hot Standby mode results in
an Active-Passive configuration. You will be required to designate one of the two DHCP servers as the
active server and the other as standby. The standby server is dormant with regard to serving client
requests as long as the active server is up.
However, the standby server receives all the inbound lease updates from the active DHCP server and
keeps its database up to date. http://blogs.technet.com/b/teamdhcp/archive/2012/09/03/dhcpfailover-hot-standbymode.aspx DHCP Failover Hot-Standby Mode In the previous blog on DHCP Failover,
we discussed the DHCP failover load balance mode where both DHCP servers respond to client requests
and load balance the requests between them based on an admin specified load distribution ratio. In the
other mode of a failover relationship, known as the Hot-Standby mode (ActivePassive), only one of the
servers actively leases IP addresses and option configuration to clients in given subnet(s)/scope(s) while
the other server (standby) is passive.
The standby server services the clients, only in event of active server being down. The clients fallback to
the active server once the active server becomes available again post the outage. The Load balance
mode is more suited for single site deployment where the 2 DHCP servers in a failover relationship are
co-located with the subnets/scopes being served by them. As the servers are in network proximity with
the clients, the clients do not experience any latency while acquiring or renewing an IP address. HotStandby mode is more suited for multisite deployment topologies. Each site would have a local DHCP
server which is configured to provide the DHCP service to the clients on the local network and DHCP
server at a remote site would be standby server. In a normal state of operation, computers and devices
on a given site receive IP addresses and other network configuration from the DHCP server located at
the same site as the clients. However, in the event of the local DHCP server being down, the DHCP
server from the remote site would provide the service to the clients. You could choose to deploy hot
standby mode in a single-site deployment also if you need to.