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iptos(4)
NAME
  iptos - Defines the IP Type Of Service (TOS) for FTP and Telnet

SYNOPSIS
  /etc/iptos

DESCRIPTION
  The /etc/iptos file configures the Type Of Service (TOS) of the Internet
  Protocol (IP) used by FTP and Telnet.

  The TOS field in the Internet datagram is to specify how the datagram
  should be handled.  It is a mechanism to allow control information to have
  precedence over data.

  Generally, protocols that are involved in direct interaction with a human
  should select low delay, while data transfers that involve large blocks of
  data need high throughput.  Finally, high reliability is most important for
  datagram-based Internet management functions.

  In the Tru64 UNIX operating system, the ftp and telnet applications and the
  ftpd and telnetd daemons allow the configuring of TOS values.	 These
  applications check to see if the /etc/iptos file exists; if the file
  exists, the applications obtain the TOS value from the file and use that
  value to set the TOS field.  If the /etc/iptos file does not exist, the
  applications default to the following TOS values recommended by RFC1060:

  ftp-control
      Low delay

  ftp-data
      High throughput

  telnet
      Low delay

  Users who want to configure their own TOS values for the TOS field should
  provide the /etc/iptos file.

				     Note
  Most IP routers do not differentiate based on TOS, and therefore providing
  values other than the default would have no affect.  You should not change
  the default values for FTP and Telnet.

  Each entry should consist of a single line of the form:

       Application  Proto  TOS-bits  aliases

  The entry fields contain the following information:

  Application
  The name of an application TOS entry.

  Proto
  The protocol name for which the entry is appropriate.

  TOS-bits
  The TOS value to be set for the entry.

  aliases
  A list of aliases that exist for the entry.

  Items on an entry line are separated by any number of blanks, tabs, or
  combination of blanks and tabs.  A number sign (#) indicates that the rest
  of the line is a comment and is not interpreted by routines that search the
  file.	 Blank lines in the file are ignored.

  Valid TOS entry names are ftp-control and ftp-data for FTP and telnet for
  Telnet.

  The TOS value for the entry should be one of the following hexadecimal
  numbers, corresponding to TOS bits:

  0x10
      Low delay

  0x08
      High throughput

  0x04
      High reliability

  If you need to disable the use of TOS bits, because you are having
  troubling communicating with a TCP/IP host that doe not conform entirely
  with the IP specification, you can disable the TOS bits by using the the
  following settings in the /etc/iptos file:

       #
       # Format of this file:
       # Application   Proto  TOS-bits	     aliases
       #

       ftp-control     tcp    0x0
       ftp-data		tcp    0x0
       telnet		  tcp	 0x0

EXAMPLES
  The following example shows typical entries in the /etc/iptos file:

       #
       # Format of this file:
       # Application   Proto  TOS-bits	     aliases
       #

       ftp-control     tcp    0x10
       ftp-data		tcp    0x08
       telnet		  tcp	 0x10

RELATED INFORMATION
  RFC1060, ftp(1), telnet(1), ftpd(8), telnetd(8)

Index for Section 4

Alphabetical listing for I

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