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LJM Specific IPs

A Note About Auto IPs

LJM 1.1500 adds the Auto IPs feature, which provides most of the benefit of specific IPs, but does so automatically. Most users should not need to edit the ljm_specific_ips.config file.

LJM Specific IPs

If LJM isn't finding an Ethernet or WiFi device during a search open (i.e. a non-specific open where "ANY" is passed for some parameters), use ljm_specific_ips.config to configure LJM to specially check specific IP addresses. LJM tries to open each IP address in ljm_specific_ips.config during relevant Open calls and ListAll calls.

Example ljm_specific_ips.config

Regardless of your computer's IP address, the following ljm_specific_ips.config file would trigger and to be checked:

// Have LJM connect to the static-IP T7...

// the lab:

// the kitchen:


  • Whitespace is ignored.

  • Empty lines and lines starting with // are ignored.

  • All other lines are expected to contain one IP address, which should not be a broadcast address.

Default Location

Windows Vista and later:


Windows XP:

C:\Documents and Settings\All Users\Application Data\LabJack\LJM\ljm_specific_ips.config

Mac OS X and Linux:


ljm_specific_ips.config is not overwritten by the installer.


For programmatically setting the file path, see LJM_SPECIFIC_IPS_FILE.

For checking if LJM has successfully read the specific IPs file, use LJM_GetSpecificIPsInfo.

Specific IPs are treated with higher priority than normal IP addresses. They checked before or during the regular UPD broadcast search and are more likely to be an Open result.

Contact your network administrator to ensure that each of the desired IPs will be reachable via TCP/UDP as a static IP address. You can also ping each address to ensure that they are reachable.


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