NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       /etc/iptos

DESCRIPTION    [Toc]    [Back]

       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: Low delay High throughput
 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: The
       name of an application TOS entry.  The protocol  name  for
       which  the  entry is appropriate.  The TOS value to be set
       for the entry.  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: Low delay
       High throughput 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    [Toc]    [Back]

       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    [Toc]    [Back]

       RFC1060, ftp(1), telnet(1), ftpd(8), telnetd(8) delim off



                                                         iptos(4)