The Offer

YIADDR Is the Offer

The offered address is an exact field in the message.

highlighted = computed this step

The offered address is a field

The yiaddr field carries the address being offered to the client.

yiaddr=192.168.1.50\text{yiaddr}=192.168.1.50
Offered addressThe toy DHCP OFFER-like fixed fields are decoded from exact bytes.Offered address144 bits / 18 bytes0x0201060012345678c0a80132001122334455byte 0byte 1byte 2byte 300000010000000010000011000000000byte 4byte 5byte 6byte 700010010001101000101011001111000byte 8byte 9byte 10byte 1111000000101010000000000100110010byte 12byte 13byte 14byte 1500000000000100010010001000110011byte 16byte 170100010001010101op2htype1hlen6hops0xid0x12345678yiaddr192.168.1.50chaddr0x001122334455(cont.)

Read the offer

The offered address is 192.168.1.50. The lesson reads it from bytes, not from prose.

offer=192.168.1.50\text{offer}=192.168.1.50
Offered addressThe toy DHCP OFFER-like fixed fields are decoded from exact bytes.Offered address144 bits / 18 bytes0x0201060012345678c0a80132001122334455byte 0byte 1byte 2byte 300000010000000010000011000000000byte 4byte 5byte 6byte 700010010001101000101011001111000byte 8byte 9byte 10byte 1111000000101010000000000100110010byte 12byte 13byte 14byte 1500000000000100010010001000110011byte 16byte 170100010001010101op2htype1hlen6hops0xid0x12345678yiaddr192.168.1.50chaddr0x001122334455(cont.)

Offer is not final ownership

An offer-shaped message proposes an address. This toy book does not model the rest of the exchange that would accept it.

offered host octet=50\text{offered host octet}=50
Offered addressThe toy DHCP OFFER-like fixed fields are decoded from exact bytes.Offered address144 bits / 18 bytes0x0201060012345678c0a80132001122334455byte 0byte 1byte 2byte 300000010000000010000011000000000byte 4byte 5byte 6byte 700010010001101000101011001111000byte 8byte 9byte 10byte 1111000000101010000000000100110010byte 12byte 13byte 14byte 1500000000000100010010001000110011byte 16byte 170100010001010101op2htype1hlen6hops0xid0x12345678yiaddr192.168.1.50chaddr0x001122334455(cont.)

Summary

The fixed fields show who the offer is for and which address is being offered.

offered=192.168.1.50\text{offered}=192.168.1.50
Offered addressThe toy DHCP OFFER-like fixed fields are decoded from exact bytes.Offered address144 bits / 18 bytes0x0201060012345678c0a80132001122334455byte 0byte 1byte 2byte 300000010000000010000011000000000byte 4byte 5byte 6byte 700010010001101000101011001111000byte 8byte 9byte 10byte 1111000000101010000000000100110010byte 12byte 13byte 14byte 1500000000000100010010001000110011byte 16byte 170100010001010101op2htype1hlen6hops0xid0x12345678yiaddr192.168.1.50chaddr0x001122334455(cont.)