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Man page of sys_attrs_inet
sys_attrs_inet
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NAME
sys_attrs_inet - inet subsystem attributes
DESCRIPTION
This reference page lists and describes attributes for the Internet
(inet) kernel subsystem. Refer to the
sys_attrs(5)
reference
page for an introduction to the topic of kernel subsystem attributes.
-
The number of hash buckets in the kernel interface alias table
(in_ifaddr). The value of the
inifaddr_hsize
attribute is always rounded down to the nearest power of 2. The
maximum value is 512.
-
Default value: 32 (hash buckets)
-
Minimum value: 16
-
Maximum value: 512 (hash buckets)
-
The default Internet Protocol (IP) time-to-live value.
-
Default value:
DEFTTL, or 64 (router hops)
-
Minimum value: 0
-
Maximum value: 255 (router hops)
-
A value that enables (1) or disables (0) a check to determine
whether an IP datagram whose destination address is a directed broadcast address
has been received on the interface corresponding to that broadcast address.
-
Default value: 0 (disabled)
-
A value that enables (1) or disables (0) a system's ability
to forward IP packets that are not addressed to the system. This functionality
is usually enabled by using the
/usr/sbin/iprsetup
command.
-
Default value: 0 (disabled)
-
For systems functioning as routers, both
ipforwarding
and
ipgateway
attributes must be 1.
-
Maximum time an IP fragment can spend waiting to be reassembled.
-
Default value:
IPFRAGTTL
(60, in units of .5 seconds,
or 30 seconds)
-
Minimum value: 1
-
Maximum value:
INT_MAX, or 2 billion
-
A value that enables (1) or disables (0) a system's ability
to forward IP packets that are not addressed to the system. This functionality
is usually enabled by using the
/usr/sbin/iprsetup
command.
-
Default value: 0 (disabled)
-
For systems functioning as routers, both
ipforwarding
and
ipgateway
attributes must be 1.
-
The number of times a system can simultaneously make outgoing
connections to other systems. The number of outgoing ports is the value of
the
ipport_userreserved
attribute minus the value of the
ipport_userreserved_min
attribute. The default value of the attribute
is 5000; therefore, the default number of outgoing ports is 3976.
-
Default value: 5000
-
Minimum value: 1
-
Maximum value: 65535
-
The lower limit of range of port numbers available for use
by a TCP or UDP application. The number of outgoing ports is the value of
the
ipport_userreserved
attribute minus the value of the
ipport_userreserved_min
attribute. The default value of the attribute
is 5000; therefore, the default number of outgoing ports is 3976.
-
Default value: 1024
-
Minimum value: 1
-
Maximum value: 65535
-
Maximum length of the IP input queue (ipintrq)
before input packets are dropped.
-
Default value: 512 (bytes)
-
Minimum value: 512
-
Maximum value: 65535
-
Maximum number of IP input queues.
-
Default value: 1 (queues)
-
Minimum value: 1
-
Maximum value: 64
-
A value that enables (1) or disables (0) the sending of ICMP
redirect messages.
-
Default value: 1 (enabled)
-
Enables (1) or disables (0) source routing.
-
Default value: 1 (enabled)
-
Time to wait after a decrease in a PMTU value before attempting
to determine if the PMTU value has increased.
-
Default value:
PMTU_DECREASE_INTVL
(in units of .5
seconds)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion
-
A value that enables (1) or disables (0) discovery of the
path maximum transfer unit (PMTU).
-
Default value: 1 (enabled)
-
Time to wait after an increase in a PMTU value before attempting
to determine if the PMTU has increased.
-
Default value:
PMTU_INCREASE_INTVL
(in units of .5
seconds)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion
-
The timer processing interval for routes participating in
the PMTU discovery process.
-
Default value:
PMTU_RT_CHECK_INTVL
(in units of .5
seconds)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion
-
A value that enables (1) or disables (0), consideration of
all IP addresses in the same network as being local. When this value is 1,
all IP addresses that are in different subnets but in the same network are
considered local. When this value is 0, only the IP addresses that match
a directly connected subnet are considered local.
-
Default value: 1 (enabled)
-
The number of Transmission Control Protocol (TCP) hash tables.
-
Default value: 1 (table)
-
Minimum value: 1
-
Maximum value: 64
-
The number of buckets in the TCP
inpcb
hash table.
-
Default value: 32 (buckets)
-
Minimum value: 0
-
Maximum value:
INT_MAX, or 2 billion
-
Enables (1) or disables (0) optimization of the listen path
for server sockets.
-
Default value: 1 (enabled)
-
A value that enables (1) or disables (0) 4.2 BSD-compatible
behavior for the initial send sequence of numbers and keepalives.
-
Default value: 1 (enabled)
-
The number of initial segments to send during congestion window
negotiation.
-
Default value: 1 (segment)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion
-
A value that enables (0) or disables (1) window scaling.
-
Default value: 0 (enabled)
-
Note that the values for disabling and enabling are the reverse of what
they are for most other attributes.
-
A value that enables (1) or disables (0) TCP keepalive for
all sockets. TCP keepalive supports the periodic transmission of messages
on a connected socket in order to keep connections active. If keepalive is
enabled, sockets that do not exit cleanly are cleaned up when the keepalive
interval expires. If keepalive is not enabled, those sockets will continue
to exist until you reboot the system.
-
Default value: 0 (disabled)
-
Applications enable keepalive for sockets by setting the
setsockopt()
function's
SO_KEEPALIVE
option.
Use the
tcp_keepalive_default
attribute to override programs
that do not set keepalive on their own, particularly if you have no access
to the sources for those programs.
-
Maximum number of keepalive probes that can be sent before
a connection is dropped.
-
Default value:
TCPTV_KEEPCNT, or 8 (probes)
-
Minimum value: 1
-
Maximum value: 32767
-
Idle time before the first keepalive probe.
-
Default value:
TCPTV_KEEP_IDLE, or 14400 (in units
of .5 seconds)
-
Minimum value: 1
-
Maximum value: 32767
-
Initial connect timeout.
-
Default value:
TCPTV_KEEP_INIT, or 150 (in units
of .5 seconds)
-
Minimum value: 1
-
Maximum value: 32767
-
Time between keepalive probes.
-
Default value:
TCPTV_KEEP_INTVL, or 150 (in units
of .5 seconds)
-
Minimum value: 1
-
Maximum value: 32767
-
The maximum lifetime of a TCP segment.
-
Default value: 60 (in units of .5 seconds)
-
Minimum value: 1
-
Maximum value: 4 billion
-
Default maximum segment size.
-
Default value:
TCP_MSS, or 536 (bytes)
-
Minimum value: 1
-
Maximum value: 2 billion
-
Default receive buffer size for TCP sockets.
-
Default value:
TCP_RECVSPACE, or 32768 (bytes)
-
Minimum value: 1
-
Maximum value: 2 billion (cannot be larger than
sb_max)
-
Minimum amount of time between TCP retransmissions.
-
Default value: 2 (in units of .5 seconds), or 1 second
-
Minimum value: 1
-
Maximum value: 2 billion
-
The maximum number of TCP retransmitted packets to send before
giving up.
-
Default value: 128 (packets)
-
Minimum value: 1
-
Maximum value:
INT_MAX, or 2 billion
-
Initial assumed round-trip time, in seconds.
-
Default value: 3 (seconds)
-
Minimum value: 0
-
Maximum value:
INT_MAX, or 2 billion
-
Default send buffer size, in bytes, for TCP sockets.
-
Default value:
TCP_SENDSPACE, or 32768 (bytes)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion (cannot be
larger than
sb_max)
-
IP time-to-live, in router hops, for TCP packets.
-
Default value:
TCP_TTL, or 60 (router hops)
-
Minimum value: 0
-
Maximum value: 255
-
A value that enables (1) or disables (0) 4.2 BSD-compatible
behavior for an urgent pointer. The urgent pointer is a pointer to the first
octet of data past the urgent section. When disabled, the urgent pointer
is a pointer to the last octet of data in the urgent section.
-
Default value: 1 (enabled)
-
A value that enables (0) or disables (1) delayed acknowledgments.
-
Default value: 0 (enabled)
-
Number of duplicate acknowledgments (ACKs) before retransmission.
-
Default value:
TCPREXMTTHRESH, or 3 (duplicate acknowledgements)
-
Minimum value: 1
-
Maximum value:
INT_MAX, or 2 billion
-
A value that enables (1) or disables (0) the movement of TCP
inpcbs
in the
TIME_WAIT
state to the
end of the
inpcb
list.
-
Default value: 0 (disabled)
-
Default receive buffer size, in bytes, for UDP sockets.
-
Default value:
UDP_RECVSPACE, or 41600 (bytes)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion (cannot be
larger than
sb_max)
-
Default send buffer size, in bytes, for UDP sockets.
-
Default value:
UDP_SENDSPACE, or 9216 (bytes)
-
Minimum value: 1
-
Maximum value:
UINT_MAX, or 4 billion (cannot be
larger than
sb_max)
-
IP time-to-live, in router hops, for UDP packets.
-
Default value:
UDP_TTL, or 30 (router hops)
-
Minimum value: 0
-
Maximum value: 255
-
A value that enables (1) or disables (0) checksumming in the
Internet user datagram protocol (UDP).
-
Default value: 1 (enabled)
SEE ALSO
sys_attrs(5)
Tuning DIGITAL UNIX for Internet Servers
at the following
location:
http://www.digital.com/internet/document/ias/tuning.html.
System Configuration and Tuning
Index
- NAME
-
- DESCRIPTION
-
- SEE ALSO
-
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Time: 02:43:09 GMT, October 02, 2010