Dhcp

ZblaJhaNiZblaJhaNi Member Posts: 35 ■■□□□□□□□□
Hi,

Regarding to the CCNP switch-official certification guide, all the client/server messages are broadcasts.

On my wireshark i can see that only DHCP discover and DHCP request are broadcasts, and the other two messages (DHCP offer & ACK) are unicasts....

Am i missing something here....?
...to the stars through difficulties...

Comments

  • CyanicCyanic Member Posts: 289
    You are right only the Discover and Request are broadcast.

    The Discover contains the MAC addy of the client, so the DHCP server does not need to broadcast.
  • ZblaJhaNiZblaJhaNi Member Posts: 35 ■■□□□□□□□□
    Hi,

    Yes this is true for Layer 2...
    I dont know, how the DHCP offer & DHCP ACK`s can be Layer 3 unicats....

    Thanks for explanation
    ...to the stars through difficulties...
  • CyanicCyanic Member Posts: 289
    It does not really matter as the host is only interested in the layer 2 address. Since the Offer and Acks are destined to the requesting host's layer 2 address, it accepts them, and process them. Layer 3 is just for routing, virtual hosts, and other higher layer processing once the frame is accepted.
  • ZblaJhaNiZblaJhaNi Member Posts: 35 ■■□□□□□□□□
    Thanks ;)
    ...to the stars through difficulties...
  • ZblaJhaNiZblaJhaNi Member Posts: 35 ■■□□□□□□□□
    one question left.
    Is DHCP option 82 enabled only, when you configure dhcp snooping?

    thanks
    ...to the stars through difficulties...
  • CyanicCyanic Member Posts: 289
    No, DHCP options are set by the host or by the relay, and they are options.

    What is DHCP Option 82? | Slaptijack

    In the case of DHCP snooping you can insert this option.
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