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Speed Bumps on the Road to Cyber Situational Awareness - Tim Bass
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lan_config(8) System Manager's Manual lan_config(8) NAME
lan_config - Modifies low-level configuration parameters for a given LAN interface SYNOPSIS
/usr/sbin/lan_config -i interface_name [-a [0 | 1]] [-m [aui | bnc | utp | fiber]] [-s [10 | 100]] [-x [0 | 1]] OPTIONS
Changes the specified characteristics for interface_name. You must provide an interface name. Enables (1) or disables (0) IEEE 802.3u autonegotiation. This option applies only to those devices that are capable of autonegotiation (for example, DE500-AA and DE500-BA). When enabled, the interface automatically negotiates the link speed (10 or 100 Mb/s) and the mode (half-duplex or full-duplex) with the remote interface. The interface initially advertises the speed and mode previously selected at the console level or with the -s and -x options. The -s and -x options may also be specified on the same command line as the -a option to redefine and renegotiate the interface's capa- bility (when enabled) or to force the interface at a certain configuration (when disabled). Note The interface initiates the autonegotiation process only if and when it is up and running. See ifconfig(8) for information on how the interface is marked up. Changes the type of medium. The following table lists the supported types: -------------------------------------------------------------- Type Meaning -------------------------------------------------------------- aui 10Base5, or thick wire bnc 10Base2, or ThinWire utp 10BaseT (if speed is 10 Mb/s) or 100BaseT (if speed is 100 Mb/s), or twisted-pair fiber 100BaseFX only -------------------------------------------------------------- On some devices, for example, DE435 and DE425, bnc selection is done by means of an on-board gang jumper. When specifying aui or bnc for these devices, be sure that the jumper is in the correct position. Changes the medium speed, if the interface is capable of operating at both regular (10 Mb/s) and fast (100 Mb/s) Ethernet speeds. The fast speed cannot be selected for the aui and bnc media. Enables (1) or disables (0) full-duplex operation when the utp medium is specified. DESCRIPTION
The lan_config command allows you to modify the type of medium, speed, and mode of operation (half- or full-duplex). You can also use the lan_config command to enable or disable autonegotiation, if the underlying device has this capability. Autonegotia- tion is a hardware and software (driver) process that allows determination of the highest common speed and duplex (half or full) configura- tion. The permitted combinations of speed and mode of operation in descending order of precedence, from the highest to the lowest, are: ----------------------- Speed Mode ----------------------- 100 Mb/s full-duplex 100 Mb/s half-duplex 10 Mb/s full-duplex 10 Mb/s half-duplex ----------------------- During autonegotiation, for example, if the local interface advertises that it is capable of 100 Mb/s half-duplex operation, it is by implication also capable of 10 Mb/s, full-duplex and 10 Mb/s, half-duplex operation. If the remote interface advertises that it is capable of 10 Mb/s, full-duplex operation only, the link is established at 10 Mb/s, full-duplex. The autonegotiation process can take several sec- onds to complete. The characteristics managed with the lan_config command are ordinarily set from the console level via the EWx0_MODE environment variable. The lan_config command allows you to override this default and configure the interface as needed after the system is up and running. Modifications made with the lan_config command do not persist across reboots of the operating system. You can also use the ifconfig command to set the speed and mode (half- or full-duplex) either from the command line or in the /etc/rc.local file. If you specify the command in the rc.local file, the command is executed each time the system is booted; you do not have to modify the SRM console environment variables. RESTRICTIONS
Support for the lan_config command is limited to the tu interface for this release of Tru64 UNIX. EXAMPLES
To switch from aui or bnc to utp full-duplex operation on tu0, enter: lan_config -i tu0 -m utp -x 1 To disable full-duplex operation on tu0, enter: lan_config -i tu0 -x 0 To enable autonegotiation on tu1, limiting capability to 100 Mb/s, enter: lan_config -i tu1 -a 1 -s 100 -x 0 To disable autonegotiation on tu1, forcing 10 Mb/s, half-duplex operation, enter: lan_config -i tu1 -a 0 -s 10 -x 1 SEE ALSO
Commands: ifconfig(8) Files: inet.local(4) Interfaces: tu(7) lan_config(8)
