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Etc/services

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'''/etc/services''' is a system file that details what named services run on which numeric ports.
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'''/etc/services''' is a system file that details what named services run on which numeric ports. The services file contains information regarding the known services available in the Internet.  For each service a single line should be present with the following information:
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official_service_name port number / protocol name aliases
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For example, say you want to know what port and protocol [[mdns]] might use:
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dave@abulafia % cat /etc/services | grep dns
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dnsix            90/tcp    #DNSIX Securit Attribute Token Map
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dnsix            90/udp    #DNSIX Securit Attribute Token Map
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sdnskmp        558/tcp
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sdnskmp        558/udp
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mdns            5353/tcp  #Multicast DNS
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mdns            5353/udp  #Multicast DNS
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You may find it tempting to inject information about every IANA port you know about into this file, but DON'T - some of the system daemons rely on the information in this file to run, and you may very well confuse them into inoperability if you dump tons of non-FreeBSD-related information into this file.  I personally figured this out the hard way when I replaced a system's /etc/services file with one I downloaded from the 'net, and it caused [[natd]] to refuse to start until I replaced my hacked-up copy with a stock copy.
 
You may find it tempting to inject information about every IANA port you know about into this file, but DON'T - some of the system daemons rely on the information in this file to run, and you may very well confuse them into inoperability if you dump tons of non-FreeBSD-related information into this file.  I personally figured this out the hard way when I replaced a system's /etc/services file with one I downloaded from the 'net, and it caused [[natd]] to refuse to start until I replaced my hacked-up copy with a stock copy.
  
[[Category:Important Config Files]]
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[[Category:Important Config Files|Services]]
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[[Category: FreeBSD Terminology]]

Latest revision as of 11:24, 4 May 2006

/etc/services is a system file that details what named services run on which numeric ports. The services file contains information regarding the known services available in the Internet. For each service a single line should be present with the following information:

official_service_name port number / protocol name aliases

For example, say you want to know what port and protocol mdns might use:

dave@abulafia % cat /etc/services | grep dns
dnsix            90/tcp    #DNSIX Securit Attribute Token Map
dnsix            90/udp    #DNSIX Securit Attribute Token Map
sdnskmp         558/tcp
sdnskmp         558/udp
mdns            5353/tcp   #Multicast DNS
mdns            5353/udp   #Multicast DNS


You may find it tempting to inject information about every IANA port you know about into this file, but DON'T - some of the system daemons rely on the information in this file to run, and you may very well confuse them into inoperability if you dump tons of non-FreeBSD-related information into this file. I personally figured this out the hard way when I replaced a system's /etc/services file with one I downloaded from the 'net, and it caused natd to refuse to start until I replaced my hacked-up copy with a stock copy.

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