TCP/IP host configuration utility
|You must be root to run this utility.|
dhcp.client [-abdHkmnRru] [-A num] [-D ident] [-h hostname] [-I num] [-i interface] [-P port] [-p port] [-s host] [-T secs] [-t num] &
The -H option could be useful in cases where the -h option is used to identify the client, and you want to apply a different hostname locally, or you simply want to ignore the server hostname assignment.
You can use this option to make dhcp.client wait until the interface it's to use is available. This is useful in a boot environment when you might not know when the driver is running and registered with the TCPIP stack. The exit status is 2 if no interface is found.
If you specify -m and -n together, the domain is added, but the nameservers aren't. If you specify -m and -k, _CS_DOMAIN isn't set.
|QNX Neutrino ignores the -r option.|
You're likely to use this option in combination with the -u option so that dhcp.client times out after a specified number of attempts.
This option is useful for spawning dhcp.client. The process doesn't move to the background until it has contacted a server and applied a TCP/IP configuration. The exit status is 3 if no server responds.
The dhcp.client obtains the TCP/IP configuration parameters dynamically from a DHCP (Dynamic Host Configuration Protocol) server, then automatically configures your TCP/IP host. You don't have to provide an IP address or any configuration parameters, or run any configuration utilities.
In a self-hosted QNX Neutrino system, dhcp.client is typically started by netmanager; you can use phlip to specify the ID and server IP address.
|This utility needs to have the setuid (“set user ID”) bit set in its permissions. If you use mkefs, mketfs, or mkifs on a Windows host to include this utility in an image, use the perms attribute to specify its permissions explicitly, and the uid and gid attributes to set the ownership correctly.|
If dhcp.client is terminated, it releases the DHCP address assigned by the server back to the server. If the client is terminated with SIGPWR, the address isn't released; the lease will timeout or be continued at client restart (depending on server policies).
|You must start io-pkt* before starting dhcp.client.|
The minimum commands to run under QNX Neutrino are:
io-pkt-v4 -dne2000 -ptcpip if_up -p enx dhcp.client & if_up enx
io-pkt-v4 -dne2000 -ptcpip dhcp.client -Ix -u
If you wish dhcp.client to apply the IP address as an alias instead of overwriting the currently assigned IP address, you must pass the -a option. This option is useful if you wish to assign multiple IP addresses to an interface. You must pass the -a option if you wish to use dhcp.client and AutoIP (lsm-autoip.so) on the same interface.
By default, dhcp.client searches for an unconfigured interface to provide service. If AutoIP is in use, an unconfigured interface will not be available, and the dhcp.client will terminate. In order for dhcp.client to provide service to an interface that already has an IP address assigned to it, use the -i option (in combination with -a), and the interface will have both a DHCP and AutoIP IP address assigned to it.
This utility obtains and implements the following information from the DHCP server:
This is an optional script that you can use to see if the DHCP configuration is correct. It should return 0 if the configuration is acceptable, or a non-zero value if it isn't (which results in a DHCPDECLINE).
Environment variables, which contain the configuration that was obtained from the server, are passed to this file. When the file is spawned, it doesn't inherit the full environment. For example, the PATH environment variable isn't available. To determine which variables are available, you can create a script such as this:
#!/bin/sh env > /tmp/config
The environment definitions are:
The following options are available but not applied by the dhcp.client process:
Any other options are defined as environment variables OPTIONx, where x is the option number. If the option is known, dhcp.client tries to format it as readable information. If the option isn't known, dhcp.client displays each octet as hexadecimal (e.g. OPTION200= F1 AA 56 42).
Currently, dhcp.client is aware of options 1 to 61.
If this file exists, it's run after a DHCP server has been contacted and the configuration options above have been applied. This file can be a binary program or a script and must be executable (see chmod). If the file is a script, the first line must be the command interpreter. For example:
The environment is the same as for dhcp-check.
This file defines the DHCP options that the client wishes to obtain from the DHCP server. You need this file only if you're adding custom DHCP option handling to the /etc/dhcp/dhcp-up file. If you add code to the dhcp-up script to handle an option, you must also add this option to /etc/dhcp/dhcp-options. The options listed in dhcp-options file are sent to the server in addition to the options:
which the dhcp.client process itself includes.
Here's an example of the dhcp-options file:
200 150 #This is a comment 90
Specify each option on its own line, listing them in order of priority. Comments must be on a separate line; they can be up to 80 characters long.
The dhcp.client utility requires the libsocket.so shared library.
Errors that occur during configuration are reported to the system log.
dhcp.client, dhcpd, /var/state/dhcp/dhcpd.leases, /etc/dhcpd.conf, io-pkt*, lsm-autoip.so, netmanager, phlip, syslogd