iptos(4)iptos(4)NAMEiptos - 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 Inter‐
net 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 appro‐
priate. 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
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) delim off
iptos(4)
