I am working for a company that deploys about a dozen workstations in a workgroup (peer-to-peer network). The workstations run Win XP. We have a DSL Internet connection, and a Cisco router that serves as the DHCP controller. The DNS is outside our firewall. We employ one software application that users access via our LAN - a customer service database application. In order for the application to succeed we are required to map a drive on the "server", i.e. the machine that is running the application and maintaining the tables. This server is not a Domain Controller - we have none, and we are not running Active Directory. We are experiencing connectivity issues with this application: we are unable to establish our full complement of licensed connections (11) and on occasion are also unable to open / view the mapped drive from a particular machine. This has led me to suspect the problem is with the LAN. My research so far has suggested that networking protocols, and perhaps Printer and File Sharing protocols are at the root of the problem. I am able to ping the application server, even at a time that I am unable to connect to the mapped drive. On the other hand, when I ran arp from a command shell, and with four successive invocations of the command "arp -a" I received three different sets of IP and MAC addresses, one list of about six IP addresses, one list of one address, and two lists of the same two addresses. It seems that something is amiss, but I don't know how to diagnose from here. Any suggestions? Thanks. CLH Title Edited - Please follow new posting rules from now on. --Zxian