04-06-2023 01:58 AM
Hi All,
Can anyone explain what dhcp option-82 is used for?
Like any specific use-cases?
I really do not see the point in using it as I have always had success relaying with out it to dhcp server.
Thanks
Solved! Go to Solution.
04-15-2023 07:11 AM
first the op-82 is add from SW or from router (relay)
for SW I explain before the use of class <<- this if need lab I can run
for Router relay I already finish lab for this case I will share here after 1-2 hrs.
04-15-2023 07:27 AM
in MPLS SP core you can use DHCP relay with op-82 to provide IP to CE depend on VRF that CE connect to.
04-15-2023 07:33 AM
ah, this makes sense now.. depending on VRF.
However in your config I did not see an option-82 entry
04-23-2023 06:37 PM
Hi @MHM Cisco World ..
I am yet to lab this and test it myself.
As soon as I do, I will update you.
Thank you again!
04-24-2023 06:11 AM
So Sorry, I see your previous comment, I will share the traffic capture to see OP-82 in real traffic.
thanks
MHM
05-09-2023
01:39 AM
- last edited on
05-11-2023
11:05 PM
by
Translator
config of lab
hostname R5-P-DHCP
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
ip dhcp pool VRF-RED
vrf RED
network 10.0.0.0 255.255.255.0
default-router 10.0.0.1
!
ip dhcp pool BLUE
vrf BLUE
network 11.0.0.0 255.255.255.0
default-router 11.0.0.1
!
!
!
no ip domain lookup
no ipv6 cef
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
no ip address
shutdown
duplex full
!
interface FastEthernet1/0
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet2/0
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet2/1
no ip address
shutdown
speed auto
duplex auto
!
interface Serial3/0
ip address 100.0.0.5 255.255.255.0
mpls ip
serial restart-delay 0
!
interface Serial3/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial3/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial3/3
ip address 200.0.0.5 255.255.255.0
mpls ip
serial restart-delay 0
!
interface GigabitEthernet4/0
no ip address
shutdown
negotiation auto
!
router ospf 100
network 100.0.0.0 0.0.0.255 area 0
network 200.0.0.0 0.0.0.255 area 0
R2-PE2#show running-config
Building configuration...
Current configuration : 1678 bytes
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname R2-PE2
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
ip cef
!
ip vrf BLUE
rd 1:100
!
!
!
ip dhcp relay information option vpn
!
!
!
no ip domain lookup
no ipv6 cef
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 2.2.2.2 255.255.255.255
!
interface FastEthernet0/0
ip vrf forwarding BLUE
ip address 11.0.0.1 255.255.255.0
ip helper-address global 200.0.0.5
duplex full
!
interface FastEthernet1/0
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet2/0
no ip address
shutdown
speed auto
duplex auto
!
interface FastEthernet2/1
no ip address
shutdown
speed auto
duplex auto
!
interface Serial3/0
no ip address
shutdown
serial restart-delay 0
!
interface Serial3/1
no ip address
shutdown
serial restart-delay 0
!
interface Serial3/2
no ip address
shutdown
serial restart-delay 0
!
interface Serial3/3
ip address 200.0.0.2 255.255.255.0
mpls ip
serial restart-delay 0
!
interface GigabitEthernet4/0
no ip address
shutdown
negotiation auto
!
router ospf 100
network 2.2.2.2 0.0.0.0 area 0
network 200.0.0.0 0.0.0.255 area 0
R4-CE2#show running-config
Building configuration...
Current configuration : 1375 bytes
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname R4-CE2
!
boot-start-marker
boot-end-marker
!
!
!
no aaa new-model
no ip icmp rate-limit unreachable
ip cef
!
!
!
!
!
!
no ip domain lookup
no ipv6 cef
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
ip tcp synwait-time 5
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
ip address dhcp
duplex full
05-09-2023 01:43 AM
05-09-2023 06:10 PM
Thanks @MHM Cisco World .. this was really helpful
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