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43 lines
1.6 KiB
TeX
43 lines
1.6 KiB
TeX
\section{DHCP Process}
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\fig{dhcp/dhcpdiscoverprocess}{dhcpdiscoverprocess}{DHCP Discover Process}
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\subsection{DHCP Messages}
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\begin{itemize}
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\item \textbf{DHCPDECLINE:} Message sent from the client to the server that the address is already in use.
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\item \textbf{DHCPNAK:} The server sends a refusal to the client for request for configuration.
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\item \textbf{DHCPRELEASE:} Client tells a server that it is giving up a lease.
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\item \textbf{DHCPINFORM:} A client already has an IP address but is requesting other configuration parameters that the DHCP server is configured to deliver such as DNS address.
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\end{itemize}
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\section{DHCP Options}
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\begin{itemize}
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\item \textbf{43} Vendor-encapsulated option that enables vendors to have their own list of options on the server.
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\item \textbf{69} SMTP server, if you want to specify available SMTP servers to the client.
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\item \textbf{70} POP3 server, if you want to specify available POP3 servers to the client.
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\item \textbf{150} TFTP server that enables your phones to access a list of TFTP servers.
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\end{itemize}
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\section{DHCP Example Configuration}
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\subsection{Cisco}
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\begin{txt}
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ip dhcp excluded-address 192.168.0.254
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!
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ip dhcp pool LAN-1-POOL-DHCP
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network 192.168.0.0 255.255.255.0
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default-router 192.168.0.254
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lease 2 ! set in days
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\end{txt}
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When configuring a Layer 3 interface as a relay port for DHCP request for a subnet. Set the ip helper command on the interface with one \textit{or} more ip addresses.
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\begin{txt}
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interface GigabitEthernet 0/3
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ip helper-address 192.168.220.220
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ip helper-address 192.168.222.222
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\end{txt}
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