DHCP option 82
DHCP option 82 contains parameters that can be set by the DHCP server and delivered to the DHCP client. Option 82 contains DHCP relay agent information.
Links
https://datatracker.ietf.org/doc/html/rfc3046
https://networklessons.com/switching/dhcp-snooping
https://networklessons.com/cisco/ccie-enterprise-infrastructure/cisco-ios-dhcp-relay-agent