Dynamic Host Configuration Protocol - Revision history

Sainis6 at 03:59, 13 April 2009

2009-04-13T03:59:39Z

← Older revision		Revision as of 03:59, 13 April 2009
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	\|colspan="4"\|OPTIONS (VARIABLE)<br />.<br />.<br />.		\|colspan="4"\|OPTIONS (VARIABLE)<br />.<br />.<br />.
	\|}		\|}
		+	<br />
		+	===DHCP State Diagram===
		+	DHCP is a stateful protocol.Refer to the folowing diagram in the following explanations.
		+
		+	[[Image:DHCP state Diagram.jpg\|DHCP state diagram<sup>[8]</sup>]]

	===DHCP Initialization===		===DHCP Initialization===
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	====DHCP Discovery====		====DHCP Discovery====
-	‭Upon connection to a network, the DHCP client will send out a broadcast message on the physical subnet to find DHCP servers. This message is in the form of a UDP DHCPDiscover packet and usually at least contains the clients MAC address in the OPTIONS section, with the broadcasted destination of 255.255.255.255 (or 0.0.0.0, depending on the implementation) or subnet broadcast address.	+	‭Upon connection to a network, the DHCP client (in the INITIALIZE state) will send out a broadcast message on the physical subnet to find DHCP servers. This message is in the form of a UDP DHCPDiscover packet and usually at least contains the clients MAC address in the OPTIONS section, with the broadcasted destination of 255.255.255.255 (or 0.0.0.0, depending on the implementation) or subnet broadcast address.

	‭If the client previously had an IP address, it can request this IP address again by placing the previous IP address in the OPTIONS section of the DHCPDiscover message. Provided the the IP address is still valid in the network, the server might grant the request. If the address is not valid,the actions taken depend on whether or not the server is set up as authoritative. An authoritative server will deny the request, causing the client to request a new IP address. A non-authoritative server will ignore the request and the client will not get a new IP until it gives up its old lease. The time before the client gives up on its old lease varies between implementations. Most modern clients, will release the IP within a few minutes and request a new IP from the server.<sup>[3]</sup>		‭If the client previously had an IP address, it can request this IP address again by placing the previous IP address in the OPTIONS section of the DHCPDiscover message. Provided the the IP address is still valid in the network, the server might grant the request. If the address is not valid,the actions taken depend on whether or not the server is set up as authoritative. An authoritative server will deny the request, causing the client to request a new IP address. A non-authoritative server will ignore the request and the client will not get a new IP until it gives up its old lease. The time before the client gives up on its old lease varies between implementations. Most modern clients, will release the IP within a few minutes and request a new IP from the server.<sup>[3]</sup>

	====DHCP Offers====		====DHCP Offers====
-	‭Upon receiving a DHCPDiscover packet from the client, the DHCP Server allocates an IP address for the client and extends an IP lease offer by sending a DHCPOFFER message to the client. The DHCPOFFER message contains the client's MAC address, the offered IP address, the subnet mask, lease duration, the IP address of the DHCP server, and any additional options, such as DNS server addresses.<sup>[3]</sup>	+	‭Upon receiving a DHCPDiscover packet from the client, the DHCP client is in the SELECT state. The DHCP Server allocates an IP address for the client and extends an IP lease offer by sending a DHCPOFFER message to the client. The DHCPOFFER message contains the client's MAC address, the offered IP address, the subnet mask, lease duration, the IP address of the DHCP server, and any additional options, such as DNS server addresses.<sup>[3]</sup>

	====DHCP requests====		====DHCP requests====
-	‭If there are multiple DHCP servers on the network, the client can receive multiple DHCPOFFERs. The client will select an offer, usually the first offer it received, and broadcast a DHCPREQUEST message. The servers on the network are informed as to which offer the client selected based on the Transaction ID field in the DHCPREQUEST message. Any Server whose offer was not selected reclaims the offered IP address.<sup>[3]</sup>	+	‭If there are multiple DHCP servers on the network, the client can receive multiple DHCPOFFERs. The client will select an offer, usually the first offer it received, and broadcast a DHCPREQUEST message. The servers on the network are informed as to which offer the client selected based on the Transaction ID field in the DHCPREQUEST message. Any Server whose offer was not selected reclaims the offered IP address.The client is now in the REQUEST state.<sup>[3]</sup>

	====DHCP acknowledgement====		====DHCP acknowledgement====
-	‭Upon receiving the DHCPREQUEST message from the client, the DHCP Server who's offer was selected sends a DHCPACK message to the client. This message contains the lease duration and any other configuration information the client requested. The IP configuration process is now complete and the client now configures its network interface with the configuration information.<sup>[3]</sup>	+	‭Upon receiving the DHCPREQUEST message from the client, the DHCP Server who's offer was selected sends a DHCPACK message to the client. This message contains the lease duration and any other configuration information the client requested. The IP configuration process is now complete and the client now configures its network interface with the configuration information. THE client is now in the BOUND state.<sup>[3]</sup>

	===Lease Renewal===		===Lease Renewal===
-	‭Upon reaching a server specified timer value (or one-half the total lease time if a value is not specified), the client will try to renew its lease by sending a DHCPREQUEST message to the server. The server will update and extend the DHCP lease time. The server then sends a DHCPACK message to the client with the new lease time. There is no limit as to how many times a client can renew its lease.	+	‭Upon reaching a server specified timer value (or one-half the total lease time if a value is not specified), the client will go to the RENEW state and the client will try to renew its lease by sending a DHCPREQUEST message to the server. The server will update and extend the DHCP lease time. The server then sends a DHCPACK message to the client with the new lease time and the client will be in the BOUND state. There is no limit as to how many times a client can renew its lease.

	‭If the client never receives an DHCPACK message, the client automatically assumes that the DHCP server is down. It will wait until 87.5% of the lease time has expired and send a DHCPREQUEST message to the server again requesting an extension to its lease time. If a negative DHCPNACK message is received by the client, the Client will immediately stop using its current IP address, and moves back to the INITIALIZE state. If the client receives a DHCPACK message, its lease has been renewed and its timers restart.		‭If the client never receives an DHCPACK message, the client automatically assumes that the DHCP server is down. It will wait until 87.5% of the lease time has expired and send a DHCPREQUEST message to the server again requesting an extension to its lease time. If a negative DHCPNACK message is received by the client, the Client will immediately stop using its current IP address, and moves back to the INITIALIZE state. If the client receives a DHCPACK message, its lease has been renewed and its timers restart.

-	‭If client does not receive a response this time, it broadcasts a DHCPREQUEST to the original server and all other DHCP servers on the network for its lease to be extended. If the client does not receive a DHCPACK message this third and final time, the lease expires. The client must relinquish the IP address and move back to the INITIALIZE state to try to acquire a new address.<sup>[3,8]</sup>	+	‭If client does not receive a response this time, it goes into the REBIND state and it broadcasts a DHCPREQUEST to the original server and all other DHCP servers on the network for its lease to be extended. If the client does not receive a DHCPACK message this third and final time, the lease expires. The client must relinquish the IP address and move back to the INITIALIZE state to try to acquire a new address.<sup>[3,8]</sup>

	===DHCP information===		===DHCP information===
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	*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)		*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
	*[http://www.iana.org/assignments/bootp-dhcp-parameters/ Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters], The Internet Assigned Numbers Authority (IANA)		*[http://www.iana.org/assignments/bootp-dhcp-parameters/ Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters], The Internet Assigned Numbers Authority (IANA)
		+
		+	--[[User:Sainis6\|Sainis6]] 23:59, 12 April 2009 (EDT)

Sainis6 at 03:47, 13 April 2009

2009-04-13T03:47:11Z

← Older revision		Revision as of 03:47, 13 April 2009
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	==Technical Details==		==Technical Details==
		+
		+	===DHCP Message===
		+	The basic format of a DHCP message is shown below. Most of the fields are self explanatory. The OP field defines if the message is a request or a reply. The HTYPE field specifies the network hardware type. HLEN is the length of the hardware address. The HOPS field is set to 0 by the client. If the machine receives the message and relays it to another machine, it increases the HOP count by 1. The Transaction ID contains an integer used to match responses with requests. The Seconds field is the number of seconds since the client began the address acquisition. The Flags field is used to specify if the message is broadcasted or not. The Router IP address is used for any relays between the server and client.The Boot FileName field is used for diskless embedded clients so they can download a specific memory image. The Options field is used for additional DHCP options.<sup>[8]</sup>
		+
		+	{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 500px;"
		+	\|+'''A DHCP Message <sup>[8]</sup>'''
		+	\|style="width:25%"\|0
		+	\|style="width:25%"\|8
		+	\|style="width:25%"\|16
		+	\|style="width:25%"\|24 <span style="float:right">31</span>
		+	\|}
		+	{\| align = "center" border="1" style="text-align:center; border-collapse: collapse; width: 500px; background-color:#bbccff;"
		+	\|-
		+	\|style="width:25%"\|OP
		+	\|style="width:25%"\|HTYPE
		+	\|style="width:25%"\|HLEN
		+	\|style="width:25%"\|HOPS
		+	\|-
		+	\|colspan="4"\|Transaction ID
		+	\|-
		+	\|colspan="2"\|Seconds
		+	\|colspan="2"\|Flags
		+	\|-
		+	\|colspan="4"\|Client IP Address
		+	\|-
		+	\|colspan="4"\|Your IP Address
		+	\|-
		+	\|colspan="4"\|Server IP Address
		+	\|-
		+	\|colspan="4"\|Router IP Address
		+	\|-
		+	\|colspan="4"\|Client Hardware Address (16 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|Server HostName (64 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|Boot FileName (128 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|OPTIONS (VARIABLE)<br />.<br />.<br />.
		+	\|}

	===DHCP Initialization===		===DHCP Initialization===
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	*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)		*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
	*[http://www.iana.org/assignments/bootp-dhcp-parameters/ Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters], The Internet Assigned Numbers Authority (IANA)		*[http://www.iana.org/assignments/bootp-dhcp-parameters/ Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters], The Internet Assigned Numbers Authority (IANA)
-
-	~~{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 100%;"~~
-	~~\|style="width:25%"\|0~~
-	~~\|style="width:25%"\|8~~
-	~~\|style="width:25%"\|16~~
-	~~\|style="width:25%"\|24 <span style="float:right">31</span>~~
-	\|}
-	~~{\| align = "center" border="1" style="text-align:center; border-collapse: collapse; width: 100%; background-color:#bbccff;"~~
-	\|-
-	~~\|style="width:25%"\|OP~~
-	~~\|style="width:25%"\|HTYPE~~
-	~~\|style="width:25%"\|HLEN~~
-	~~\|style="width:25%"\|HOPS~~
-	\|-
-	~~\|colspan="4"\|Transaction ID~~
-	\|-
-	~~\|colspan="2"\|Seconds~~
-	~~\|colspan="2"\|Flags~~
-	\|-
-	~~\|colspan="4"\|Client IP Address~~
-	\|-
-	~~\|colspan="4"\|Your IP Address~~
-	\|-
-	~~\|colspan="4"\|Server IP Address~~
-	\|-
-	~~\|colspan="4"\|Router IP Address~~
-	\|-
-	~~\|colspan="4"\|Client Hardware Address (16 OCTETS)<br />.<br />.<br />.~~
-	\|-
-	~~\|colspan="4"\|Server HostName (64 OCTETS)<br />.<br />.<br />.~~
-	\|-
-	~~\|colspan="4"\|Boot FileName (128 OCTETS)<br />.<br />.<br />.~~
-	\|-
-	~~\|colspan="4"\|OPTIONS (VARIABLE)<br />.<br />.<br />.~~
-	\|}

Sainis6 at 03:29, 13 April 2009

2009-04-13T03:29:36Z

← Older revision		Revision as of 03:29, 13 April 2009
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	\|-		\|-
	\|colspan="4"\|Client IP Address		\|colspan="4"\|Client IP Address
		+	\|-
		+	\|colspan="4"\|Your IP Address
		+	\|-
		+	\|colspan="4"\|Server IP Address
		+	\|-
		+	\|colspan="4"\|Router IP Address
		+	\|-
		+	\|colspan="4"\|Client Hardware Address (16 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|Server HostName (64 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|Boot FileName (128 OCTETS)<br />.<br />.<br />.
		+	\|-
		+	\|colspan="4"\|OPTIONS (VARIABLE)<br />.<br />.<br />.
	\|}		\|}

Sainis6 at 03:24, 13 April 2009

2009-04-13T03:24:48Z

← Older revision		Revision as of 03:24, 13 April 2009
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	==History==		==History==

-	‭DHCP was created by the Dynamic Host Configuration Working Group at the [http://www.ietf.org/ Internet Engineering Task Force (IETF;] a volunteer organization which defines protocols for use on the Internet). It was originally defined in RFC 1531 in October 1993 as a superset of the BOOTstrap Protocol (BOOTP). It was further refined with corrections and more options in RFC 1541 in the same month. The current definition of DHCP for IPv4 networks is in RFC 2131, released in March 1997. Various DHCP options available as of March 1997 are discussed in RFC 2132. DHCPv6, the extension of DHCP for [[The Future of the Internet: IPv6\|IPv6], is defined in RFC 3315.<sup>[2,3]</sup>	+	‭DHCP was created by the Dynamic Host Configuration Working Group at the [http://www.ietf.org/ Internet Engineering Task Force (IETF;] a volunteer organization which defines protocols for use on the Internet). It was originally defined in RFC 1531 in October 1993 as a superset of the BOOTstrap Protocol (BOOTP). It was further refined with corrections and more options in RFC 1541 in the same month. The current definition of DHCP for IPv4 networks is in RFC 2131, released in March 1997. Various DHCP options available as of March 1997 are discussed in RFC 2132. DHCPv6, the extension of DHCP for [[The Future of the Internet: IPv6\|IPv6]], is defined in RFC 3315.<sup>[2,3]</sup>

	===The Need For DHCP===		===The Need For DHCP===
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	Besides, the cleaner implementation, DHCPv6 has some key advantages over DHCPv4. In DHCPv6 all interfaces on a client can be configured with one exchange with each interface having different options. DHCPv6 allows DHCPv6 packets to have options encapsulated at many different levels. DHCPv6 allows normal address allocation, as well as temporary address allocation, which allows the use of a IPv6 privacy address. Privacy addresses allow a network user to generate a new unique IPv6 address periodically or for each session.<sup>[10]</sup>		Besides, the cleaner implementation, DHCPv6 has some key advantages over DHCPv4. In DHCPv6 all interfaces on a client can be configured with one exchange with each interface having different options. DHCPv6 allows DHCPv6 packets to have options encapsulated at many different levels. DHCPv6 allows normal address allocation, as well as temporary address allocation, which allows the use of a IPv6 privacy address. Privacy addresses allow a network user to generate a new unique IPv6 address periodically or for each session.<sup>[10]</sup>

-	Many features of [[[The Future of the Internet: IPv6\|IPv6]] help to improve DHCPv6. IPv6 hosts have link-local addresses where every network interface has a unique address. As such, IPv6 hosts can use its link-local address to send requests to the DHCPv6 Server for a network valid IPv6 address. IPv4 clients must use system specific hacks before they have an address. All IPv6 networks support multicasting, so DHCPv6 servers are able to recieve only DHCPv6 multicast packets. This allows the server to know where to send packets. In IPv4, when a clients broadcast a request, the server does not know how far to send an offer. These features allow a more efficient implementation of DHCP.<sup>[9]</sup>	+	Many features of [[The Future of the Internet: IPv6\|IPv6]] help to improve DHCPv6. IPv6 hosts have link-local addresses where every network interface has a unique address. As such, IPv6 hosts can use its link-local address to send requests to the DHCPv6 Server for a network valid IPv6 address. IPv4 clients must use system specific hacks before they have an address. All IPv6 networks support multicasting, so DHCPv6 servers are able to recieve only DHCPv6 multicast packets. This allows the server to know where to send packets. In IPv4, when a clients broadcast a request, the server does not know how far to send an offer. These features allow a more efficient implementation of DHCP.<sup>[9]</sup>

	===DHCPv6 vs IPv6 Autoconfiguration===		===DHCPv6 vs IPv6 Autoconfiguration===
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	*[http://www.docs.hp.com/en/B2355-90685/ch06s02.html DHCP Components and Concepts], HP docs		*[http://www.docs.hp.com/en/B2355-90685/ch06s02.html DHCP Components and Concepts], HP docs
	*[http://ou800doc.caldera.com/en/NET_tcpip/dhcpN.intro.html Configuring a Dynamic Host Configuration Protocol (DHCP) server], SCO UnixWare 7 Documentation		*[http://ou800doc.caldera.com/en/NET_tcpip/dhcpN.intro.html Configuring a Dynamic Host Configuration Protocol (DHCP) server], SCO UnixWare 7 Documentation
		+	*RFC 951, Bootstrap Protocol (BOOTP)
	*RFC 2131, Dynamic Host Configuration Protocol		*RFC 2131, Dynamic Host Configuration Protocol
		+	*RFC 2132, DHCP Options and BOOTP Vendor Extensions
		+	*RFC 2461, IPv6 Stateless Address Autoconfiguration
	*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)		*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
		+	*[http://www.iana.org/assignments/bootp-dhcp-parameters/ Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters], The Internet Assigned Numbers Authority (IANA)

	{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 100%;"		{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 100%;"

Sainis6 at 03:20, 13 April 2009

2009-04-13T03:20:10Z

← Older revision		Revision as of 03:20, 13 April 2009
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	==History==		==History==

-	‭DHCP was created by the Dynamic Host Configuration Working Group at the [http://www.ietf.org/ Internet Engineering Task Force (IETF;] a volunteer organization which defines protocols for use on the Internet). It was originally defined in RFC 1531 in October 1993 as a superset of the BOOTstrap Protocol (BOOTP). It was further refined with corrections and more options in RFC 1541 in the same month. The current definition of DHCP for IPv4 networks is in RFC 2131, released in March 1997. Various DHCP options available as of March 1997 are discussed in RFC 2132. DHCPv6, the extension of DHCP for IPv6, is defined in RFC 3315.<sup>[2,3]</sup>	+	‭DHCP was created by the Dynamic Host Configuration Working Group at the [http://www.ietf.org/ Internet Engineering Task Force (IETF;] a volunteer organization which defines protocols for use on the Internet). It was originally defined in RFC 1531 in October 1993 as a superset of the BOOTstrap Protocol (BOOTP). It was further refined with corrections and more options in RFC 1541 in the same month. The current definition of DHCP for IPv4 networks is in RFC 2131, released in March 1997. Various DHCP options available as of March 1997 are discussed in RFC 2132. DHCPv6, the extension of DHCP for [[The Future of the Internet: IPv6\|IPv6], is defined in RFC 3315.<sup>[2,3]</sup>

	===The Need For DHCP===		===The Need For DHCP===
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	Besides, the cleaner implementation, DHCPv6 has some key advantages over DHCPv4. In DHCPv6 all interfaces on a client can be configured with one exchange with each interface having different options. DHCPv6 allows DHCPv6 packets to have options encapsulated at many different levels. DHCPv6 allows normal address allocation, as well as temporary address allocation, which allows the use of a IPv6 privacy address. Privacy addresses allow a network user to generate a new unique IPv6 address periodically or for each session.<sup>[10]</sup>		Besides, the cleaner implementation, DHCPv6 has some key advantages over DHCPv4. In DHCPv6 all interfaces on a client can be configured with one exchange with each interface having different options. DHCPv6 allows DHCPv6 packets to have options encapsulated at many different levels. DHCPv6 allows normal address allocation, as well as temporary address allocation, which allows the use of a IPv6 privacy address. Privacy addresses allow a network user to generate a new unique IPv6 address periodically or for each session.<sup>[10]</sup>

-	Many features of IPv6 help to improve DHCPv6. IPv6 hosts have link-local addresses where every network interface has a unique address. As such, IPv6 hosts can use its link-local address to send requests to the DHCPv6 Server for a network valid IPv6 address. IPv4 clients must use system specific hacks before they have an address. All IPv6 networks support multicasting, so DHCPv6 servers are able to recieve only DHCPv6 multicast packets. This allows the server to know where to send packets. In IPv4, when a clients broadcast a request, the server does not know how far to send an offer. These features allow a more efficient implementation of DHCP.<sup>[9]</sup>	+	Many features of [[[The Future of the Internet: IPv6\|IPv6]] help to improve DHCPv6. IPv6 hosts have link-local addresses where every network interface has a unique address. As such, IPv6 hosts can use its link-local address to send requests to the DHCPv6 Server for a network valid IPv6 address. IPv4 clients must use system specific hacks before they have an address. All IPv6 networks support multicasting, so DHCPv6 servers are able to recieve only DHCPv6 multicast packets. This allows the server to know where to send packets. In IPv4, when a clients broadcast a request, the server does not know how far to send an offer. These features allow a more efficient implementation of DHCP.<sup>[9]</sup>

	===DHCPv6 vs IPv6 Autoconfiguration===		===DHCPv6 vs IPv6 Autoconfiguration===

Sainis6 at 03:19, 13 April 2009

2009-04-13T03:19:03Z

← Older revision		Revision as of 03:19, 13 April 2009
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	#[http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-2/ipv6_autoconfig.html IPv6 Autoconfiguration], Cisco, François Donzé, Retrieved on April 12th 2009		#[http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-2/ipv6_autoconfig.html IPv6 Autoconfiguration], Cisco, François Donzé, Retrieved on April 12th 2009
	#[http://learn-networking.com/network-design/dynamic-host-configuration-protocol An Introduction to Dynamic Host Configuration Protocol], Learn Networking, Retrieved on April 12th 2009		#[http://learn-networking.com/network-design/dynamic-host-configuration-protocol An Introduction to Dynamic Host Configuration Protocol], Learn Networking, Retrieved on April 12th 2009
		+
	==External links==		==External links==
		+	*[http://www.tcpipguide.com/free/t_TCPIPDynamicHostConfigurationProtocolDHCP.htm TCP/IP Dynamic Host Configuration Protocol (DHCP)] The TCP/IP Guide
		+	*[http://www.bind9.net/dhcp DHCP Articles, DHCP Links, DHCP Whitepapers], Bind9.net
		+	*[http://www.networksorcery.com/enp/protocol/dhcp.htm DHCP, Dynamic Host Configuration Protocol], RFC Sourcebook
		+	*[http://support.microsoft.com/kb/169289 DHCP (Dynamic Host Configuration Protocol) Basics], Microsoft Support
		+	*[http://docs.huihoo.com/opensolaris/system-administration-guide-ip-services/html/p65.html About Solaris DHCP (Overview)], SUN Microsystems docs
		+	*[http://www.docs.hp.com/en/B2355-90685/ch06s02.html DHCP Components and Concepts], HP docs
		+	*[http://ou800doc.caldera.com/en/NET_tcpip/dhcpN.intro.html Configuring a Dynamic Host Configuration Protocol (DHCP) server], SCO UnixWare 7 Documentation
		+	*RFC 2131, Dynamic Host Configuration Protocol
		+	*RFC 3315, Dynamic Host Configuration Protocol for IPv6 (DHCPv6)

	{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 100%;"		{\| align = "center" cellspacing="0" cellpadding="0" border="0" style="text-align:left; width: 100%;"