©!Men!&!Mice!!http://menandmice.com!
Windows!2012!DHCP!Failover
1
©!Men!&!Mice!!http://menandmice.com!
Agenda
•a!reliable!DHCP!service
•centralized!vs.!
decentralized!DHCP
•setting!up!a!DH...
©!Men!&!Mice!!http://menandmice.com!
The!need!for!redundancy
•A!single!DHCP!Server!is,!well,!a!single!point!of!failure
•ma...
©!Men!&!Mice!!http://menandmice.com!
Centralized!vs.!distributed!
DHCP
Branch!A
DHCP!
Server
DHCP!
Client
4
©!Men!&!Mice!!http://menandmice.com!
Centralized!vs.!distributed!
DHCP
Branch!B
HQ
Branch!A
A!distributed!(or!de-
centrali...
©!Men!&!Mice!!http://menandmice.com!
Centralized!vs.!distributed!
DHCP
Branch!B
HQ
Branch!A
A!centralized!DHCP!System
DHCP...
©!Men!&!Mice!!http://menandmice.com!
Centralized!vs.!de-centralized!
DHCP
•in!the!1990ties,!most!DHCP!deployments!were!de-...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
Branch!B
HQ
Branch!A
A!distributed!(or!de-
centralized)!DHCP!S...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
•having!redundant!DHCP!Servers!in!every!network!is!
possible,!...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
Branch!B
HQ
Branch!A
A!distributed!(or!de-
centralized)!DHCP!S...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
•the!key!to!redundant!DHCP!server!deployments!are!relay!
agent...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
10.0.0.254
Router...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
backup DHCP Server
10.0.0.1
Server
10.0.0.10
DHCP Server
192.1...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
•the!challenge!when!building!redundant!DHCP!servers!is!
the!“l...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
•Solution!1:!using!static!DHCP
•one!possible!solution!is!to!us...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
Branch!B
HQ
Branch!A
static!DHCP host computer {
hardware ethe...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
• Solution!1:!using!static!DHCP
• Pros:
• works!with!any!numbe...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
•Solution!2:!split!pools
•the!available!addresses!are!split!ac...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
Branch!B
HQ
Branch!A
split!pools!with!a!80/20!split
subnet 192...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
• Solution!2:!using!split!pools
• Pros:
• works!with!any!numbe...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
•Solution!3:!DHCP!cluster
•some!DHCP!products!can!use!a!failov...
©!Men!&!Mice!!http://menandmice.com!
Redundant!DHCP!Servers
Branch!B
HQ
Branch!A
DHCP!server!with!failover!
protocol
DHCP!...
©!Men!&!Mice!!http://menandmice.com!
DHCP!Server!redundancy
•Solution!3:!using!a!DHCP!failover!cluster
•Pros:
•optimal!uti...
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
•the!Failover!protocol!can!be!con...
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
31
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
32
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
33
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
34
©!Men!&!Mice!!http://menandmice.com!
Configuring!the!Failover!
Protocol!in!Windows!2012!
• Max!client!lead!time:!the!time!...
©!Men!&!Mice!!http://menandmice.com!
Failover!modes
•the!Windows!2012!DHCP!Server!can!be!configured!to!run!in!
two!differe...
©!Men!&!Mice!!http://menandmice.com!
Failover!modes
•in!a!load!balancing!configuration,!the!split!(number!of!IP!
address!l...
©!Men!&!Mice!!http://menandmice.com!
Failover!modes
•in!a!hot-standby!configuration!most!addresses!are!
managed!by!the!pri...
©!Men!&!Mice!!http://menandmice.com!
Failover!protocol
39
©!Men!&!Mice!!http://menandmice.com!
Failover!protocol
40
©!Men!&!Mice!!http://menandmice.com!
Men!&!Mice!DHCP!Workshop!
Training
• 3!day!“hands-on”!training!including
• a!througho...
©!Men!&!Mice!!http://menandmice.com!
Questions?
E-Mail:
carsten@menandmice.com
42
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Windows 2012 and DHCP Failover

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Reliable DHCP Service, centralized vs. decentralized DHCP, setting up a DHCP relay agent, using static DHCP address allocation, Failover cluster with Windows 2012

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Transcript of "Windows 2012 and DHCP Failover"

  1. 1. ©!Men!&!Mice!!http://menandmice.com! Windows!2012!DHCP!Failover 1
  2. 2. ©!Men!&!Mice!!http://menandmice.com! Agenda •a!reliable!DHCP!service •centralized!vs.! decentralized!DHCP •setting!up!a!DHCP!relay! agent •using!static!DHCP! address!allocation •Split-Scopes •Failover-Cluster!with! Windows!2012 2
  3. 3. ©!Men!&!Mice!!http://menandmice.com! The!need!for!redundancy •A!single!DHCP!Server!is,!well,!a!single!point!of!failure •many!devices!might!not!get!an!IP!Address!and!network! configuration!if!the!DHCP!Server!fails •there!are!several!ways!to!make!a!DHCP!service!redundant! 3
  4. 4. ©!Men!&!Mice!!http://menandmice.com! Centralized!vs.!distributed! DHCP Branch!A DHCP! Server DHCP! Client 4
  5. 5. ©!Men!&!Mice!!http://menandmice.com! Centralized!vs.!distributed! DHCP Branch!B HQ Branch!A A!distributed!(or!de- centralized)!DHCP!System 5
  6. 6. ©!Men!&!Mice!!http://menandmice.com! Centralized!vs.!distributed! DHCP Branch!B HQ Branch!A A!centralized!DHCP!System DHCP! Relay DHCP! Server 6
  7. 7. ©!Men!&!Mice!!http://menandmice.com! Centralized!vs.!de-centralized! DHCP •in!the!1990ties,!most!DHCP!deployments!were!de- centralized •today,!due!to!the!increased!reliability!of!network!links,! we!see!more!centralized!deployments •but!for!certain!businesses!(retail!stores),!de-centralized! deployments!are!still!in!use 7
  8. 8. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers Branch!B HQ Branch!A A!distributed!(or!de- centralized)!DHCP!System DHCP! Server backup DHCP! Server 8
  9. 9. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers •having!redundant!DHCP!Servers!in!every!network!is! possible,!but!expensive!it!terms!of!hardware!and! maintenance •backup!DHCP!Servers!are!therefore!often!shared!across! networks 9
  10. 10. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers Branch!B HQ Branch!A A!distributed!(or!de- centralized)!DHCP!System DHCP! Server backup! DHCP!Server for!A/B/HQ DHCP! Relay 10
  11. 11. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers •the!key!to!redundant!DHCP!server!deployments!are!relay! agents •software!based!relay!agents!(ISC!DHCP!relay!agent) •router!(Cisco,!Juniper,!HP,!3COM!...)!based!relay!agents 11
  12. 12. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 unicast UDP DHCPDISCOVER 12
  13. 13. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 DHCPOFFER 13
  14. 14. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 DHCPREQUEST 14
  15. 15. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 DHCPACK Workstation 0.0.0.0 Workstation 192.168.1.10 15
  16. 16. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 unicast UDP DHCPDISCOVER 16
  17. 17. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 DHCPOFFER 17
  18. 18. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 10.0.0.254 Router with relay agent 192.168.1.254 DHCP Server 192.168.1.1 Workstation 0.0.0.0 DHCPREQUEST 18
  19. 19. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers backup DHCP Server 10.0.0.1 Server 10.0.0.10 DHCP Server 192.168.1.1 DHCPACK Workstation 0.0.0.0 Workstation 192.168.1.10 10.0.0.254 Router with relay agent 192.168.1.254 19
  20. 20. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy •the!challenge!when!building!redundant!DHCP!servers!is! the!“lease!state”!held!by!the!DHCP!Servers! •if!more!than!one!DHCP!Server!gives!out!IP!Addresses! for!the!same!network,!each!server!most!“know”!the! leases!the!other!servers!have!given!out 20
  21. 21. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy •Solution!1:!using!static!DHCP •one!possible!solution!is!to!use!all!static!DHCP!(no! dynamic!address!pools) •every!machine!gets!a!host!definition!with!a!fixed- address!statement!(so!called!“reservation”) •the!host!definition!is!distributed!to!all!DHCP!Servers 21
  22. 22. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers Branch!B HQ Branch!A static!DHCP host computer { hardware ethernet 00:0d:93:c0:cb:f8; fixed-address 192.168.1.25; } DHCP! Relay host computer { hardware ethernet 00:0d:93:c0:cb:f8; fixed-address 192.168.1.25; } host computer { hardware ethernet 00:0d:93:c0:cb:f8; fixed-address 192.168.1.25; } 22
  23. 23. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy • Solution!1:!using!static!DHCP • Pros: • works!with!any!number!of!DHCP!Servers,!even!with!a!mix!of!different! products • simple • Cons • high!management!overhead • no!dynamic!address!pools 23
  24. 24. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy •Solution!2:!split!pools •the!available!addresses!are!split!across!DHCP!Servers •no!two!DHCP!Servers!are!authoritative!for!the!same!IP! Addresses •the!split!depends!on!the!lease!times!used!and!the!time!it! takes!to!re-build!a!broken!DHCP!Server •a!simple!scheme!is!the!80/20!split 24
  25. 25. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers Branch!B HQ Branch!A split!pools!with!a!80/20!split subnet 192.0.2.0/24 pool 192.0.2.1-192.0.2.200 DHCP! Relay subnet 10.0.1.0/24 pool 10.0.1.1-10.0.1.200 subnet 10.0.1.0/24 pool 10.0.1.201-10.0.1.250 subnet 192.0.2.0/24 pool 192.0.2.201-192.0.2.250 25
  26. 26. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy • Solution!2:!using!split!pools • Pros: • works!with!any!number!of!DHCP!Servers,!even!with!a!mix!of!different! products • allows!dynamic!address!pools • Cons • high!management!overhead • IP!space!is!not!optimal!utilized 26
  27. 27. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy •Solution!3:!DHCP!cluster •some!DHCP!products!can!use!a!failover!protocol!to! synchronize!their!state!with!a!cluster!peer •the!Windows!2012!DHCP!Server!supports!a!failover! protocol!(RFC!3074) •the!full!number!of!available!IP!Addresses!can!be!used! for!the!dynamic!address!pools 27
  28. 28. ©!Men!&!Mice!!http://menandmice.com! Redundant!DHCP!Servers Branch!B HQ Branch!A DHCP!server!with!failover! protocol DHCP! Relay Failover “heartbeat” Failover “heartbeat” 28
  29. 29. ©!Men!&!Mice!!http://menandmice.com! DHCP!Server!redundancy •Solution!3:!using!a!DHCP!failover!cluster •Pros: •optimal!utilization!of!the!IP!address!space •Cons •failover!only!available!between!compatible!products •more!complex 29
  30. 30. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! •the!Failover!protocol!can!be!configured!for!every!IPv4! scope!between!two!DHCP!server!(DHCP!Failover!peers) •there!is!no!failover!protocol!for!IPv6!(there!is!enough! space!per!/64!for!split!scope!configurations) •the!IETF!is!working!on!a!DHCPv6!failover!protocol 30
  31. 31. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! 31
  32. 32. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! 32
  33. 33. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! 33
  34. 34. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! 34
  35. 35. ©!Men!&!Mice!!http://menandmice.com! Configuring!the!Failover! Protocol!in!Windows!2012! • Max!client!lead!time:!the!time!a! DHCP!failover!peer!can!extend!a! know!lease!to!a!client!in!case!the! partner!is!down • a!high!value!slows!down! recovery • a!low!value!causes!more!DHCP! traffic!on!the!remaining!failover! peer 35
  36. 36. ©!Men!&!Mice!!http://menandmice.com! Failover!modes •the!Windows!2012!DHCP!Server!can!be!configured!to!run!in! two!different!failover!modes •load-balance:!both!servers!are!active!and!are!giving!out!leases •hot-standby:!only!the!primary!machine!is!active,!the!backup! standby!DHCP!server!is!waiting!to!take!over!in!the!case!of!an! failure!on!the!primary!DHCP!server 36
  37. 37. ©!Men!&!Mice!!http://menandmice.com! Failover!modes •in!a!load!balancing!configuration,!the!split!(number!of!IP! address!leases)!can!be!configured!between!the!failover! peers 37
  38. 38. ©!Men!&!Mice!!http://menandmice.com! Failover!modes •in!a!hot-standby!configuration!most!addresses!are! managed!by!the!primary!server •the!standby!server!holds!a!number!of!reserved! addresses!for!new!clients!that!appear!in!the!failover! case 38
  39. 39. ©!Men!&!Mice!!http://menandmice.com! Failover!protocol 39
  40. 40. ©!Men!&!Mice!!http://menandmice.com! Failover!protocol 40
  41. 41. ©!Men!&!Mice!!http://menandmice.com! Men!&!Mice!DHCP!Workshop! Training • 3!day!“hands-on”!training!including • a!throughout!introduction!into!DHCP • DHCP!clients!(Windows!XP/Vista/7/8,!Linux,!MacOS!X,!Android,!iPhone/iPad!...) • DHCP!Server!(ISC!DHCP!3.x!and!4.x,!Microsoft!DHCP!2008/2012,!ISC!BIND!10!DHCP,!Cisco!IOS!DHCP) • DHCP!and!DNS!interaction • DHCP!and!IPv6 • DHCP!operations!(monitoring,!troubleshooting,!tools) • many!“hands-on”!labs • For!prices!and!dates • go!to!http://menandmice.com/training/ 41
  42. 42. ©!Men!&!Mice!!http://menandmice.com! Questions? E-Mail: carsten@menandmice.com 42

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