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# 1  
Old 07-09-2002
Question TCP/UDP Ports

Just wondering if anyone knows of any good on-line documentation on TCP/UDP Ports. Basically i want to know how to check if they are in use, learn how to close them, etc...
# 2  
Old 07-09-2002
Try this link (Rutgers University) and do a search for lsof (either on your system or on Goggle ) - lsof is a program that lists open files (a port is a file in UNIX)
# 3  
Old 07-19-2002

try this link for tcp/ip
# 4  
Old 08-01-2002
Here is my favorite link for TCP/UDP ports:
# 5  
Old 08-25-2002
Quickest way to see if a port is in use is to simply use the 'netstat' command and grep for the port you are interested in. Also note that port alias names can be configured in '/etc/services' thus if a port does not appear to be in use check if an alias exists and grep accordingly.
# 6  
Old 08-26-2002
Many implimentations of netstat have the -n flag that causes netstat to not look up a common name in /etc/services.
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