Wednesday, November 22, 2017

Should option 43 Always be recieved in a DHCP offer?

Looking at RFC3925, option 43 responses are offered when an option 60 attribute are specified by the client.

Now most vendor implementations indicate that option 60 must be configured on the server end as well as the client, except for juniper who indicate it only needs to be configured on the client’s end, and do not make the option available when setting the pool

Most wireless vendor articles on the subject indicate that a server will ONLY reply with option 43 when a client sends and option 60 that is also configured on the server end.

See this DHCP offer from a MS DHCP server to an Aruba AP which has broadcast a DHCP REQUEST with the option 60 field set on both the client and server end.

this to me looks like the correct behaviour of option 60 & 43.

Now when i plug my win10 laptop into the same network and request an ip address from the same server, I receive the same option 43 response back even though the win10 option 60 field is not set on the DHCP server. the option 60 response is also not sent back to the win10 client.

so, my questions are;

  1. what is the correct interpretation of the RFC?

  2. should servers respond with option 43 to clients whose option 60 attribute is not set on the server?



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