The client’s hardware address field (chaddr) in the DHCPv4 header is generated by the SR OS:
The first 2 bytes of the MAC address are 02:03.
The remaining 4 bytes are the hash result of IKEv2 IDi.
The following options are included in the DHCPv4 packets sent by the SR OS:
Option 82 circuit-id (private-SAP-id | private-interface-name; for example, tunnel-1.private:100 | priv-int)
Option 82 remote-id (IKEv2 IDi in text format)
Option 61 client-id is 1 byte that represents the IKEv2 IDi type plus the IKEv2 IDi in text format. The value of the first byte is as follows:
ID_IPV4_ADDR = 1
ID_DER_ASN1_DN = 2
ID_FQDN = 3
ID_RFC822_ADDR = 4
ID_IPV6_ADDR = 5