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ns-tcpParam

The following operations can be performed on "ns-tcpParam":

set| unset| show|

set ns tcpParam

Sets the TCP parameters for the Citrix ADC.

Synopsis

set ns tcpParam [-WS ( ENABLED | DISABLED )] [-WSVal ] [-SACK ( ENABLED | DISABLED )] [-learnVsvrMSS ( ENABLED | DISABLED )] [-maxBurst ] [-initialCwnd ] [-delayedAck ] [-downStateRST ( ENABLED | DISABLED )] [-nagle ( ENABLED | DISABLED )] [-limitedPersist ( ENABLED | DISABLED )] [-oooQSize ] [-ackOnPush ( ENABLED | DISABLED )] [-maxPktPerMss ] [-pktPerRetx ] [-minRTO ] [-slowStartIncr ] [-maxDynServerProbes ] [-synHoldFastGiveup ] [-maxSynholdPerprobe ] [-maxSynhold ] [-mssLearnInterval ] [-mssLearnDelay ] [-maxTimeWaitConn ] [-maxSynAckRetx ] [-synAttackDetection ( ENABLED | DISABLED )] [-connFlushIfNoMem ] [-connFlushThres ] [-mptcpConCloseOnPassiveSF ( ENABLED | DISABLED )] [-mptcpChecksum ( ENABLED | DISABLED )] [-mptcpSFtimeout ] [-mptcpSFReplaceTimeout ] [-mptcpMaxSF ] [-mptcpMaxPendingSF ] [-mptcpPendingJoinThreshold ] [-mptcpRTOsToSwitchSF ] [-mptcpUseBackupOnDSS ( ENABLED | DISABLED )] [-TcpMaxRetries ] [-mptcpImmediateSFCloseOnFIN ( ENABLED | DISABLED )] [-mptcpCloseMptcpSessionOnLastSFClose ( ENABLED | DISABLED )] [-mptcpSendSFResetOption ( ENABLED | DISABLED )] [-mptcpFastCloseOption ( ACK | RESET )] [-tcpFastOpenCookieTimeout ] [-autosyncookietimeout ] [-tcpFinTimeout ] [-compactTcpOptionNoop ( ENABLED | DISABLED )] [-delinkClientServerOnRST ( ENABLED | DISABLED )]

Arguments

WS Enable or disable window scaling.

Possible values: ENABLED, DISABLED Default value: ENABLED

WSVal Factor used to calculate the new window size. This argument is needed only when the window scaling is enabled. Default value: 8 Minimum value: 0 Maximum value: 14

SACK Enable or disable Selective ACKnowledgement (SACK).

Possible values: ENABLED, DISABLED Default value: ENABLED

learnVsvrMSS Enable or disable maximum segment size (MSS) learning for virtual servers.

Possible values: ENABLED, DISABLED Default value: DISABLED

maxBurst Maximum number of TCP segments allowed in a burst. Default value: 6 Minimum value: 1 Maximum value: 255

initialCwnd Initial maximum upper limit on the number of TCP packets that can be outstanding on the TCP link to the server. Default value: 10 Minimum value: 1 Maximum value: 44

delayedAck Timeout for TCP delayed ACK, in milliseconds. Default value: 100 Minimum value: 10 Maximum value: 300

downStateRST Flag to switch on RST on down services.

Possible values: ENABLED, DISABLED Default value: DISABLED

nagle Enable or disable the Nagle algorithm on TCP connections.

Possible values: ENABLED, DISABLED Default value: DISABLED

limitedPersist Limit the number of persist (zero window) probes.

Possible values: ENABLED, DISABLED Default value: ENABLED

oooQSize Maximum size of out-of-order packets queue. A value of 0 means no limit. Default value: 300 Minimum value: 0 Maximum value: 65535

ackOnPush Send immediate positive acknowledgement (ACK) on receipt of TCP packets with PUSH flag.

Possible values: ENABLED, DISABLED Default value: ENABLED

maxPktPerMss Maximum number of TCP packets allowed per maximum segment size (MSS). Minimum value: 0 Maximum value: 1460

pktPerRetx Maximum limit on the number of packets that should be retransmitted on receiving a partial ACK. Default value: 1 Minimum value: 1 Maximum value: 100

minRTO Minimum retransmission timeout, in milliseconds, specified in 10-millisecond increments (value must yield a whole number if divided by 10). Default value: 1000 Minimum value: 10 Maximum value: 64000

slowStartIncr Multiplier that determines the rate at which slow start increases the size of the TCP transmission window after each acknowledgement of successful transmission. Default value: 2 Minimum value: 1 Maximum value: 100

maxDynServerProbes Maximum number of probes that Citrix ADC can send out in 10 milliseconds, to dynamically learn a service. Citrix ADC probes for the existence of the origin in case of wildcard virtual server or services. Default value: 7 Minimum value: 1 Maximum value: 65535

synHoldFastGiveup Maximum threshold. After crossing this threshold number of outstanding probes for origin, the Citrix ADC reduces the number of connection retries for probe connections. Default value: 1024 Minimum value: 256 Maximum value: 65535

maxSynholdPerprobe Limit the number of client connections (SYN) waiting for status of single probe. Any new SYN packets will be dropped. Default value: 128 Minimum value: 1 Maximum value: 255

maxSynhold Limit the number of client connections (SYN) waiting for status of probe system wide. Any new SYN packets will be dropped. Default value: 16384 Minimum value: 256 Maximum value: 65535

mssLearnInterval Duration, in seconds, to sample the Maximum Segment Size (MSS) of the services. The Citrix ADC determines the best MSS to set for the virtual server based on this sampling. The argument to enable maximum segment size (MSS) for virtual servers must be enabled. Default value: 180 Minimum value: 1 Maximum value: 1048576

mssLearnDelay Frequency, in seconds, at which the virtual servers learn the Maximum segment size (MSS) from the services. The argument to enable maximum segment size (MSS) for virtual servers must be enabled. Default value: 3600 Minimum value: 1 Maximum value: 1048576

maxTimeWaitConn Maximum number of connections to hold in the TCP TIME_WAIT state on a packet engine. New connections entering TIME_WAIT state are proactively cleaned up. Default value: 7000 Minimum value: 1

maxSynAckRetx When 'syncookie' is disabled in the TCP profile that is bound to the virtual server or service, and the number of TCP SYN+ACK retransmission by Citrix ADC for that virtual server or service crosses this threshold, the Citrix ADC responds by using the TCP SYN-Cookie mechanism. Default value: 100 Minimum value: 100 Maximum value: 1048576

synAttackDetection Detect TCP SYN packet flood and send an SNMP trap.

Possible values: ENABLED, DISABLED Default value: ENABLED

connFlushIfNoMem Flush an existing connection if no memory can be obtained for new connection.

HALF_CLOSED_AND_IDLE: Flush a connection that is closed by us but not by peer, or failing that, a connection that is past configured idle time. New connection fails if no such connection can be found.

FIFO: If no half-closed or idle connection can be found, flush the oldest non-management connection, even if it is active. New connection fails if the oldest few connections are management connections.

Note: If you enable this setting, you should also consider lowering the zombie timeout and half-close timeout, while setting the Citrix ADC timeout.

See Also: connFlushThres argument below.

Possible values: NONE , HALFCLOSED_AND_IDLE, FIFO Default value: NSA_CONNFLUSH_NONE

connFlushThres Flush an existing connection (as configured through -connFlushIfNoMem FIFO) if the system has more than specified number of connections, and a new connection is to be established. Note: This value may be rounded down to be a whole multiple of the number of packet engines running. Minimum value: 1

mptcpConCloseOnPassiveSF Accept DATA_FIN/FAST_CLOSE on passive subflow

Possible values: ENABLED, DISABLED Default value: ENABLED

mptcpChecksum Use MPTCP DSS checksum

Possible values: ENABLED, DISABLED Default value: ENABLED

mptcpSFtimeout The timeout value in seconds for idle mptcp subflows. If this timeout is not set, idle subflows are cleared after cltTimeout of vserver Default value: 0 Maximum value: 31536000

mptcpSFReplaceTimeout The minimum idle time value in seconds for idle mptcp subflows after which the sublow is replaced by new incoming subflow if maximum subflow limit is reached. The priority for replacement is given to those subflow without any transaction Default value: 10 Maximum value: 31536000

mptcpMaxSF Maximum number of subflow connections supported in established state per mptcp connection. Default value: 4 Minimum value: 2 Maximum value: 6

mptcpMaxPendingSF Maximum number of subflow connections supported in pending join state per mptcp connection. Default value: 4 Minimum value: 0 Maximum value: 4

mptcpPendingJoinThreshold Maximum system level pending join connections allowed. Default value: 0 Minimum value: 0 Maximum value: 4294967294

mptcpRTOsToSwitchSF Number of RTO's at subflow level, after which MPCTP should start using other subflow. Default value: 2 Minimum value: 1 Maximum value: 6

mptcpUseBackupOnDSS When enabled, if NS receives a DSS on a backup subflow, NS will start using that subflow to send data. And if disabled, NS will continue to transmit on current chosen subflow. In case there is some error on a subflow (like RTO's/RST etc.) then NS can choose a backup subflow irrespective of this tunable.

Possible values: ENABLED, DISABLED Default value: ENABLED

TcpMaxRetries Number of RTO's after which a connection should be freed. Default value: 7 Minimum value: 1 Maximum value: 7

mptcpImmediateSFCloseOnFIN Allow subflows to close immediately on FIN before the DATA_FIN exchange is completed at mptcp level.

Possible values: ENABLED, DISABLED Default value: DISABLED

mptcpCloseMptcpSessionOnLastSFClose Allow to send DATA FIN or FAST CLOSE on mptcp connection while sending FIN or RST on the last subflow.

Possible values: ENABLED, DISABLED Default value: DISABLED

mptcpSendSFResetOption Allow MPTCP subflows to send TCP RST Reason (MP_TCPRST) Option while sending TCP RST.

Possible values: ENABLED, DISABLED Default value: DISABLED

mptcpFastCloseOption Allow to select option ACK or RESET to force the closure of an MPTCP connection abruptly.

Possible values: ACK, RESET Default value: ACK

tcpFastOpenCookieTimeout Timeout in seconds after which a new TFO Key is computed for generating TFO Cookie. If zero, the same key is used always. If timeout is less than 120seconds, NS defaults to 120seconds timeout. Default value: 0 Minimum value: 0 Maximum value: 31536000

autosyncookietimeout Timeout for the server to function in syncookie mode after the synattack. This is valid if TCP syncookie is disabled on the profile and server acts in non syncookie mode by default. Default value: 30 Minimum value: 7 Maximum value: 65535

tcpFinTimeout The amount of time in seconds, after which a TCP connnection in the TCP TIME-WAIT state is flushed. Default value: 40 Minimum value: 10 Maximum value: 240

compactTcpOptionNoop If enabled, non-negotiated TCP options are removed from the received packet while proxying it. By default, non-negotiated TCP options would be replaced by NOPs in the proxied packets. This option is not applicable for Citrix ADC generated packets.

Possible values: ENABLED, DISABLED Default value: DISABLED

delinkClientServerOnRST If enabled, Delink client and server connection, when there is outstanding data to be sent to the other side.

Possible values: ENABLED, DISABLED Default value: DISABLED

unset ns tcpParam

Use this command to remove ns tcpParam settings.Refer to the set ns tcpParam command for meanings of the arguments.

Synopsis

unset ns tcpParam [-WS] [-WSVal] [-SACK] [-learnVsvrMSS] [-maxBurst] [-initialCwnd] [-delayedAck] [-downStateRST] [-nagle] [-limitedPersist] [-oooQSize] [-ackOnPush] [-maxPktPerMss] [-pktPerRetx] [-minRTO] [-slowStartIncr] [-maxDynServerProbes] [-synHoldFastGiveup] [-maxSynholdPerprobe] [-maxSynhold] [-mssLearnInterval] [-mssLearnDelay] [-maxTimeWaitConn] [-maxSynAckRetx] [-synAttackDetection] [-connFlushIfNoMem] [-connFlushThres] [-mptcpConCloseOnPassiveSF] [-mptcpChecksum] [-mptcpSFtimeout] [-mptcpSFReplaceTimeout] [-mptcpMaxSF] [-mptcpMaxPendingSF] [-mptcpPendingJoinThreshold] [-mptcpRTOsToSwitchSF] [-mptcpUseBackupOnDSS] [-TcpMaxRetries] [-mptcpImmediateSFCloseOnFIN] [-mptcpCloseMptcpSessionOnLastSFClose] [-mptcpSendSFResetOption] [-mptcpFastCloseOption] [-tcpFastOpenCookieTimeout] [-autosyncookietimeout] [-tcpFinTimeout] [-compactTcpOptionNoop] [-delinkClientServerOnRST]

show ns tcpParam

Displays the TCP parameters configured on the Citrix ADC.

Synopsis

show ns tcpParam

Arguments

Output

WS Enable or disable window scaling.

WSVal Factor used to calculate the new window size. This argument is needed only when the window scaling is enabled.

SACK Enable or disable Selective ACKnowledgement (SACK).

learnVsvrMSS Enable or disable maximum segment size (MSS) learning for virtual servers.

maxBurst Maximum number of TCP segments allowed in a burst.

initialCwnd Initial maximum upper limit on the number of TCP packets that can be outstanding on the TCP link to the server.

recvBuffSize TCP Receive buffer size

delayedAck Timeout for TCP delayed ACK, in milliseconds.

downStateRST Flag to switch on RST on down services.

nagle Enable or disable the Nagle algorithm on TCP connections.

limitedPersist Limit the number of persist (zero window) probes.

oooQSize Maximum size of out-of-order packets queue. A value of 0 means no limit.

ackOnPush Immediate ACK on PUSH packet

maxPktPerMss Maximum packets per MSS

pktPerRetx Maximum packets per retransmission

minRTO Minimum retransmission timeout, in milliseconds, specified in 10-millisecond increments (value must yield a whole number if divided by 10).

slowStartIncr TCP slowstart increment factor

maxDynServerProbes Maximum number of probes that Citrix ADC can send out in 10 milliseconds, to dynamically learn a service. Citrix ADC probes for the existence of the origin in case of wildcard virtual server or services.

synHoldFastGiveup Maximum threshold. After crossing this threshold number of outstanding probes for origin, the Citrix ADC reduces the number of connection retries for probe connections.

maxSynholdPerprobe Limit the number of client connections (SYN) waiting for status of single probe. Any new SYN packets will be dropped.

maxSynhold Limit the number of client connections (SYN) waiting for status of probe system wide. Any new SYN packets will be dropped.

mssLearnInterval Duration, in seconds, to sample the Maximum Segment Size (MSS) of the services. The Citrix ADC determines the best MSS to set for the virtual server based on this sampling. The argument to enable maximum segment size (MSS) for virtual servers must be enabled.

mssLearnDelay Frequency, in seconds, at which the virtual servers learn the Maximum segment size (MSS) from the services. The argument to enable maximum segment size (MSS) for virtual servers must be enabled.

maxTimeWaitConn Maximum number of connections to hold in the TCP TIME_WAIT state on a packet engine. New connections entering TIME_WAIT state are proactively cleaned up.

KAprobeUpdateLastactivity Update last activity for KA probes

maxSynAckRetx When 'syncookie' is disabled in the TCP profile that is bound to the virtual server or service, and the number of TCP SYN+ACK retransmission by Citrix ADC for that virtual server or service crosses this threshold, the Citrix ADC responds by using the TCP SYN-Cookie mechanism.

synAttackDetection Detect TCP SYN packet flood and send an SNMP trap.

connFlushIfNoMem Flush an existing connection if no memory can be obtained for new connection.

HALF_CLOSED_AND_IDLE: Flush a connection that is closed by us but not by peer, or failing that, a connection that is past configured idle time. New connection fails if no such connection can be found.

FIFO: If no half-closed or idle connection can be found, flush the oldest non-management connection, even if it is active. New connection fails if the oldest few connections are management connections.

Note: If you enable this setting, you should also consider lowering the zombie timeout and half-close timeout, while setting the Citrix ADC timeout.

See Also: connFlushThres argument below.

connFlushThres Flush an existing connection (as configured through -connFlushIfNoMem FIFO) if the system has more than specified number of connections, and a new connection is to be established. Note: This value may be rounded down to be a whole multiple of the number of packet engines running.

mptcpConCloseOnPassiveSF Accept DATA_FIN/FAST_CLOSE on passive subflow

mptcpChecksum Use MPTCP DSS checksum

mptcpSFtimeout The timeout value in seconds for idle mptcp subflows. If this timeout is not set, idle subflows are cleared after cltTimeout of vserver

mptcpSFReplaceTimeout The minimum idle time value in seconds for idle mptcp subflows after which the sublow is replaced by new incoming subflow if maximum subflow limit is reached. The priority for replacement is given to those subflow without any transaction

mptcpMaxSF Maximum number of subflow connections supported in established state per mptcp connection.

mptcpMaxPendingSF Maximum number of subflow connections supported in pending join state per mptcp connection.

mptcpPendingJoinThreshold Maximum system level pending join connections allowed.

mptcpRTOsToSwitchSF Number of RTO's at subflow level, after which MPCTP should start using other subflow.

mptcpUseBackupOnDSS When enabled, if NS receives a DSS on a backup subflow, NS will start using that subflow to send data. And if disabled, NS will continue to transmit on current chosen subflow. In case there is some error on a subflow (like RTO's/RST etc.) then NS can choose a backup subflow irrespective of this tunable.

TcpMaxRetries Number of RTO's after which a connection should be freed.

mptcpImmediateSFCloseOnFIN Allow subflows to close immediately on FIN before the DATA_FIN exchange is completed at mptcp level.

mptcpCloseMptcpSessionOnLastSFClose Allow to send DATA FIN or FAST CLOSE on mptcp connection while sending FIN or RST on the last subflow.

mptcpSendSFResetOption Allow MPTCP subflows to send TCP RST Reason (MP_TCPRST) Option while sending TCP RST.

mptcpFastCloseOption Allow to select option ACK or RESET to force the closure of an MPTCP connection abruptly.

tcpFastOpenCookieTimeout Timeout in seconds after which a new TFO Key is computed for generating TFO Cookie. If zero, the same key is used always. If timeout is less than 120seconds, NS defaults to 120seconds timeout.

builtin Flag to determine if the tcp param is built-in or not

feature The feature to be checked while applying this config

autosyncookietimeout Timeout for the server to function in syncookie mode after the synattack. This is valid if TCP syncookie is disabled on the profile and server acts in non syncookie mode by default.

tcpFinTimeout The amount of time in seconds, after which a TCP connnection in the TCP TIME-WAIT state is flushed.

compactTcpOptionNoop If enabled, non-negotiated TCP options are removed from the received packet while proxying it. By default, non-negotiated TCP options would be replaced by NOPs in the proxied packets. This option is not applicable for Citrix ADC generated packets.

delinkClientServerOnRST If enabled, Delink client and server connection, when there is outstanding data to be sent to the other side.

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