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To be able to find Lantronix device servers the PC running Device Installer (DI) should have an IP-address in the same range as the Device Severs that you try to discover.
By default Device Servers will assign themselves an IP-address in the range 169.254.x.x if they do not get an IP-address from a DHCP-server (router).
To discover Device Servers who auto-assigned a 169.254 IP-address you can set the IP-address of your PC to an address on the same subnet, e.g. 169.254.1.100.
See also the following FAQ for alternative ways to assign IP-addresses to the UDS1100:
Answer Title: Assigning an IP address to a CoBos product
Answer Link: Assigning an IP address to a CoBos product
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