DHCP: Forskelle mellem versioner

 

== Lag placering i ISOs OSI-model ==

 

Protokollen kan under en DHCP-forhandling starte med ikke-routebare source ([[0.0.0.0]]) og destinations ([[255.255.255.255]]) ip-adresser i lag 3-headeren, men kan senere benytte routebare ip-adresser. Herudover indeholder DHCP-pakker også valide [[UDP]]-porte. DHCP-protokollen kan starte med at respektere lag 2-protokollen og kan ende med at bootstrappe sig til at respektere lag 3 (IPv4) og lag 4 UDP-protokollen.<ref>[http://tools.ietf.org/html/rfc2131 RFC 2131] Citat: "...The server MUST broadcast the DHCPNAK message to the 0xffffffff broadcast address because the client may not have a correct network address or subnet mask, and the client may not be answering ARP requests...Normally, DHCP servers and BOOTP relay agents attempt to deliver DHCPOFFER, DHCPACK and DHCPNAK messages directly to the client using u[n]icast delivery...If the BROADCAST bit is cleared to 0, the message SHOULD be sent as an IP unicast to the IP address specified in the 'yiaddr' field..."</ref><ref>[http://www.eventhelix.com/RealtimeMantra/Networking/DHCP.pdf DHCP Sequence Diagram] – This sequence diagram covers several scenarios of DHCP operation.</ref>