Editing Dynamic Host Configuration Protocol (section)

===Offer===
When a DHCP server receives a DHCPDISCOVER message from a client, which is an IP address lease request, the DHCP server reserves an IP address for the client and makes a lease offer by sending a DHCPOFFER message to the client. This message may contain the client's ''Client ID'' (Option 61, containing a unique value, traditionally a MAC address), the IP address that the server is offering, the subnet mask, the lease duration, and the IP address of the DHCP server making the offer. The DHCP server may also take notice of the hardware-level MAC address (as specified in the CHADDR field). This field must be used to identify the client, if no Client ID is provided in the DHCP packet.{{Ref RFC|2131|rsection=4.2}}

The DHCP server determines the configuration based on the client's hardware address as specified in the CHADDR (client hardware address) field. In the following example the server ({{IPaddr|192.168.1.1}}) specifies the client's IP address in the YIADDR (your IP address) field.
{{APHD|start|title=Example Ethernet frame with a DHCPOFFER message}}
{{APHD|0|bits1=32|border1=bottom|field1=Source MAC|value1={{MACaddr|b4:0c:25:e3:7d:62}}}}
{{APHD|4|bits1=16|border1=top|field1={{nbsp}}|bits2=16|border2=bottom|field2={{nbsp}}}}
{{APHD|8|bits1=32|border1=top|field1=Destination MAC|value1={{MACaddr|00:05:3c:04:8d:59}}}}
{{APHD|12|bits1=16|field1=EtherType|value1={{Mono|0x0800}}|hint1=0x0800 indicates IPv4|bits2=16|border2=bottom|background2=mistyrose|field2={{nbsp}}}}
{{APHD|16|bits1=0|border1=top|background1=mistyrose|field1=IPv4 packet, containing a UDP PDU with DHCP payload...}}
{{APHD|999|bits1=32|field1=Frame Check Sequence|short1=FCS}}
{{APHD|end}}
{{APHD|start|header=yew|title=IPv4 Header}}
{{APHD|0|bits1=64|field1=IPv4 header start}}
{{APHD|8|bits1=8|bits2=8|bits3=16|field1=TTL|field2=Protocol ({{Mono|17}} UDP)|field3=Header Checksum}}
{{APHD|end}}
{{APHD|start|header=no|title=UDP Header}}
{{APHD|12|bits1=32|field1=Source Address ({{IPaddr|192.168.1.1}})}}
{{APHD|16|bits1=32|field1=Destination Address ({{IPaddr|192.168.1.100}})}}
{{APHD|20|bits1=16|bits2=16|field1=Source Port (67)|field2=Destination Port (68)}}
{{APHD|24|bits1=16|bits2=16|field1=Length|field2=Checksum}}
{{APHD|end}}
{{APHD|start|header=no|title=DHCP Payload: DHCPOFFER}}
{{APHD|28|bits1=8|bits2=8|bits3=8|bits4=8|field1=OP ({{Mono|0x02}})|hint1=BOOTREPLY|field2=HTYPE ({{Mono|0x01}})|field3=HLEN ({{Mono|0x06}})|field4=HOPS ({{Mono|0x00}})}}
{{APHD|32|bits1=32|field1=XID ({{Mono|0x3903F326}})}}
{{APHD|36|bits1=16|bits2=16|field1=SECS ({{Mono|0x0000}})|field2=FLAGS ({{Mono|0x0000}})}}
{{APHD|40|bits1=32|field1=CIADDR (Client IP address: {{Mono|0x00000000}})}}
{{APHD|44|bits1=32|field1=YIADDR  (Your IP address: {{Mono|0xC0A80164}} or {{IPaddr|192.168.1.100}})}}
{{APHD|48|bits1=32|field1=SIADDR (Server IP address: {{Mono|0xC0A80101}} or {{IPaddr|192.168.1.1}})}}
{{APHD|52|bits1=32|field1=GIADDR (Gateway IP address: {{Mono|0x00000000}})}}
{{APHD|56|bits1=128|field1=CHADDR (Client Hardware address: {{Mono|0x00053C04<br>0x8D590000<br>0x00000000<br>0x00000000}})}}
{{APHD|72|bits1=1536|field1=192 octets of 0s, or overflow space for additional options; BOOTP legacy.}}
{{APHD|264|bits1=32|field1=[[Magic Cookie]] ({{Mono|0x63825363}})}}
{{APHD|end}}
{{APHD|start|header=no|title=DHCP Options (in [[Type-length-value|TLV]] format)}}
{{APHD|268|bits1=24|background1=linen|field1=First option: {{Mono|0x350102}}: Option 53 (DHCP Message Type) 1 octet (containing DHCPOFFER)|bits2=8|background2=linen|border2=right|field2=Second option:}}
{{APHD|272|bits1=32|background1=linen|border1=left|field1={{Mono|0x0104ffffff00}}: Option 1 (Subnet mask) 4 octets (containing {{IPaddr|255.255.255.0}})}}
{{APHD|276|bits1=32|background1=linen|field1=Third option: {{Mono|0x0304c0A80101}}: Option: 3 (Router) 4 octets (containing {{IPaddr|192.168.1.1}})|border1=right}}
{{APHD|280|bits1=8|bits2=24|background1=linen|border1=left|field1=Router cont...||background2=linen|border2=right|field2=Fourth option: {{Mono|0x330400015080}}: Option 51 (Address time) 4 octets (a 86400 second lease time)}}
{{APHD|284|bits1=16|background1=linen|border1=left|field1=Address time cont...|bits2=16|border2=bottom|field2=Fifth option:|background2=linen}}
{{APHD|288|bits1=96|background1=linen|border1=top-bottom|field1={{Mono|0x060c09070a0f09070a1009070a13}}:{{Break}}Option 6 (Domain Server) 14 octets (containing {{IPaddr|9.7.10.15}},{{IPaddr|9.7.10.16}},{{IPaddr|9.7.10.18}})}}
{{APHD|300|bits1=12|background1=linen|field1=&nbsp;|border1=top|field2=<small>{{Mono|ff}}</small>|hint2=0xff Option end mark}}
{{APHD|end}}