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<concept id="GUID-69B46D92-8D07-5B42-B603-3F725977AA4A" xml:lang="en"><title>DHCP</title><shortdesc>The Dynamic Host Configuration Protocol (DHCP) is an Internet standard

defined in RFC2131 (IPv4) and RFC3315 (IPv6). </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>The DHCP client implementation in Symbian platform enables the client applications

to configure a network connection with a DHCP server. </p>

<p>For more details on the DHCP standards, see RFC2131<xref href="http://www.ietf.org/rfc/rfc2131.txt" scope="external">RFC2131</xref> for IPv4, and RFC3315<xref href="http://www.ietf.org/rfc/rfc3315.txt" scope="external">RFC3315</xref> for IPv6.</p>

<p>This document explains the following concepts: </p>

<ul>

<li id="GUID-77B3171B-FCF4-5744-B288-AFCC81B93488"><p>DHCP States </p> </li>

<li id="GUID-460F04A8-5FF1-578F-B129-3C61264044D4"><p>DHCP Options </p> </li>

</ul>

<section id="GUID-D83FB908-53EC-4019-A8E4-8B633FEC7F0B"><title>DHCP States </title> <p>The following are the states of the

DHCP daemon in Symbian OS: </p> <ul>

<li id="GUID-ACD085A9-E25C-58A8-859E-1E42BC467089"><p>DHCP Discover </p> </li>

<li id="GUID-18AAC18A-9A29-5B5D-AEC1-E64B8A81A149"><p>Bind </p> </li>

<li id="GUID-04DF8A2D-4CCD-59A3-8346-CF7D5E1F176C"><p>Renew lease </p> </li>

<li id="GUID-56E8EDB9-EBF7-5A66-B85B-E0685BED0C6C"><p>Release lease </p> </li>

</ul> <p><b>DHCP Discover </b> </p> <p>This stage gets the IP address from

the server by the DHCP clients. The DHCP client sends a DISCOVER message to

the DHCP server and waits for the responses from the various DHCP servers. </p> <p><b>Bind </b> </p> <p>The

DHCP server acknowledges the BIND request with an IP address. The client selects

one of the IP addresses and responds back with a BIND message. If the DHCP

server acknowledges the BIND request, the client can use the IP address. If

the server responds with a negative acknowledgement, the DHCP client begins

the DHCP DISCOVER state. </p> <p><b>Renew lease </b> </p> <p>The DHCP server

issues an IP address, called a lease, during the bind state. When the lease

is about to expire the client requests the server to renew the lease. If the

client is connected to the same network the lease gets renewed. If the client

has moved to a domain with a different DHCP server the client requests a new

IP address using DISCOVER message. </p> <p><b>Release lease </b> </p> <p>When

the DHCP client does not require a connection it releases the lease, so that

it can be configured to any other client requesting a connection. </p> </section>

<section id="GUID-C5F11CA2-8880-4FDB-8065-149C5EAA7A44"><title>DHCP Options</title> <p>To obtain the network parameters from

the DHCP server, the client uses the DHCP options. The Internet standard <xref href="http://www.ietf.org/rfc/rfc2132.txt" scope="external">RFC 2132</xref> specifies

the various DHCP options. The client uses the <xref href="GUID-95F9FA1F-5AA5-3C2F-ADE0-34668B499C50.dita"><apiname>aOptionLevel</apiname></xref> and <xref href="GUID-DA7EBA40-EF88-3C95-9361-E3A199783CE2.dita"><apiname>aOptionName</apiname></xref> arguments

while calling <xref href="GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD.dita#GUID-BED8A733-2ED7-31AD-A911-C1F4707C67FD/GUID-9F820CF9-1D4F-3452-983B-E0C694D6783A"><apiname>RConnection::Ioctl()</apiname></xref> function. </p> </section>

</conbody><related-links>

<link href="GUID-45E1953A-DEFB-5E48-AC96-443A3234F913.dita"><linktext>Retrieving

an IP Network  Parameters</linktext></link>

</related-links></concept>