Hi, below you will find the key parameters to get two squid instances working. Both as services running parallel (listening on different ports) under W2K3. The pid_filename tag was the key to success ;-) Thanks to Armin Marxer, especially for the quick help! Stefan the setup (Squid Cache version 2.5.STABLE10-NT for i686-pc-winnt): ######################################################################## ########## Instance 1: D:/squid-direct/ as directory structure command line for starting squid: squid -f d:/squid-direct/etc/squid.conf Installing as a service: D:\squid-direct\sbin>squid -i -f d:/squid-direct/etc/squid.conf -n squidDirect snippet from conf: # NETWORK OPTIONS # ------------------------------------------------------------------------ ----- http_port 80 # LOGFILE PATHNAMES AND CACHE DIRECTORIES # ------------------------------------------------------------------------ ----- cache_dir ufs d:/squid-direct/var/spool/squid 300 16 256 cache_access_log d:/squid-direct/var/logs/squid/access.log cache_log d:/squid-direct/var/logs/squid/cache.lo # TAG: pid_filename # A filename to write the process-id to. To disable, enter "none". # #Default: pid_filename d:/squid-direct/var/logs/squid.pid ######################################################################## ########## Instance 2: D:/squid-peer/ as directory structure command line for starting squid: squid -f d:/squid-peer/etc/squid.conf Installing as a service: D:\squid-peer\sbin>squid -i -f d:/squid-peer/etc/squid.conf -n squidPeer snippet from conf: # NETWORK OPTIONS # ------------------------------------------------------------------------ ----- http_port 3128 # LOGFILE PATHNAMES AND CACHE DIRECTORIES # ------------------------------------------------------------------------ ----- cache_dir ufs d:/squid-peer/var/spool/squid 300 16 256 cache_access_log d:/squid-peer/var/logs/squid/access.log cache_log d:/squid-peer/var/logs/squid/cache.log # TAG: pid_filename # A filename to write the process-id to. To disable, enter "none". # #Default: pid_filename d:/squid-peer/var/logs/squid.pid ######################################################################## ##########