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-rw-r--r--Documentation/networking/ip-sysctl.txt66
1 files changed, 47 insertions, 19 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index c7fc10724948..dbca66182089 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -30,16 +30,24 @@ neigh/default/gc_thresh3 - INTEGER
30 Maximum number of neighbor entries allowed. Increase this 30 Maximum number of neighbor entries allowed. Increase this
31 when using large numbers of interfaces and when communicating 31 when using large numbers of interfaces and when communicating
32 with large numbers of directly-connected peers. 32 with large numbers of directly-connected peers.
33 Default: 1024
33 34
34neigh/default/unres_qlen_bytes - INTEGER 35neigh/default/unres_qlen_bytes - INTEGER
35 The maximum number of bytes which may be used by packets 36 The maximum number of bytes which may be used by packets
36 queued for each unresolved address by other network layers. 37 queued for each unresolved address by other network layers.
37 (added in linux 3.3) 38 (added in linux 3.3)
39 Setting negative value is meaningless and will return error.
40 Default: 65536 Bytes(64KB)
38 41
39neigh/default/unres_qlen - INTEGER 42neigh/default/unres_qlen - INTEGER
40 The maximum number of packets which may be queued for each 43 The maximum number of packets which may be queued for each
41 unresolved address by other network layers. 44 unresolved address by other network layers.
42 (deprecated in linux 3.3) : use unres_qlen_bytes instead. 45 (deprecated in linux 3.3) : use unres_qlen_bytes instead.
46 Prior to linux 3.3, the default value is 3 which may cause
47 unexpected packet loss. The current default value is calculated
48 according to default value of unres_qlen_bytes and true size of
49 packet.
50 Default: 31
43 51
44mtu_expires - INTEGER 52mtu_expires - INTEGER
45 Time, in seconds, that cached PMTU information is kept. 53 Time, in seconds, that cached PMTU information is kept.
@@ -199,15 +207,16 @@ tcp_early_retrans - INTEGER
199 Default: 2 207 Default: 2
200 208
201tcp_ecn - INTEGER 209tcp_ecn - INTEGER
202 Enable Explicit Congestion Notification (ECN) in TCP. ECN is only 210 Control use of Explicit Congestion Notification (ECN) by TCP.
203 used when both ends of the TCP flow support it. It is useful to 211 ECN is used only when both ends of the TCP connection indicate
204 avoid losses due to congestion (when the bottleneck router supports 212 support for it. This feature is useful in avoiding losses due
205 ECN). 213 to congestion by allowing supporting routers to signal
214 congestion before having to drop packets.
206 Possible values are: 215 Possible values are:
207 0 disable ECN 216 0 Disable ECN. Neither initiate nor accept ECN.
208 1 ECN enabled 217 1 Always request ECN on outgoing connection attempts.
209 2 Only server-side ECN enabled. If the other end does 218 2 Enable ECN when requested by incoming connections
210 not support ECN, behavior is like with ECN disabled. 219 but do not request ECN on outgoing connections.
211 Default: 2 220 Default: 2
212 221
213tcp_fack - BOOLEAN 222tcp_fack - BOOLEAN
@@ -215,15 +224,14 @@ tcp_fack - BOOLEAN
215 The value is not used, if tcp_sack is not enabled. 224 The value is not used, if tcp_sack is not enabled.
216 225
217tcp_fin_timeout - INTEGER 226tcp_fin_timeout - INTEGER
218 Time to hold socket in state FIN-WAIT-2, if it was closed 227 The length of time an orphaned (no longer referenced by any
219 by our side. Peer can be broken and never close its side, 228 application) connection will remain in the FIN_WAIT_2 state
220 or even died unexpectedly. Default value is 60sec. 229 before it is aborted at the local end. While a perfectly
221 Usual value used in 2.2 was 180 seconds, you may restore 230 valid "receive only" state for an un-orphaned connection, an
222 it, but remember that if your machine is even underloaded WEB server, 231 orphaned connection in FIN_WAIT_2 state could otherwise wait
223 you risk to overflow memory with kilotons of dead sockets, 232 forever for the remote to close its end of the connection.
224 FIN-WAIT-2 sockets are less dangerous than FIN-WAIT-1, 233 Cf. tcp_max_orphans
225 because they eat maximum 1.5K of memory, but they tend 234 Default: 60 seconds
226 to live longer. Cf. tcp_max_orphans.
227 235
228tcp_frto - INTEGER 236tcp_frto - INTEGER
229 Enables Forward RTO-Recovery (F-RTO) defined in RFC4138. 237 Enables Forward RTO-Recovery (F-RTO) defined in RFC4138.
@@ -495,7 +503,7 @@ tcp_fastopen - INTEGER
495tcp_syn_retries - INTEGER 503tcp_syn_retries - INTEGER
496 Number of times initial SYNs for an active TCP connection attempt 504 Number of times initial SYNs for an active TCP connection attempt
497 will be retransmitted. Should not be higher than 255. Default value 505 will be retransmitted. Should not be higher than 255. Default value
498 is 6, which corresponds to 63seconds till the last restransmission 506 is 6, which corresponds to 63seconds till the last retransmission
499 with the current initial RTO of 1second. With this the final timeout 507 with the current initial RTO of 1second. With this the final timeout
500 for an active TCP connection attempt will happen after 127seconds. 508 for an active TCP connection attempt will happen after 127seconds.
501 509
@@ -1323,6 +1331,12 @@ force_tllao - BOOLEAN
1323 race condition where the sender deletes the cached link-layer address 1331 race condition where the sender deletes the cached link-layer address
1324 prior to receiving a response to a previous solicitation." 1332 prior to receiving a response to a previous solicitation."
1325 1333
1334ndisc_notify - BOOLEAN
1335 Define mode for notification of address and device changes.
1336 0 - (default): do nothing
1337 1 - Generate unsolicited neighbour advertisements when device is brought
1338 up or hardware address changes.
1339
1326icmp/*: 1340icmp/*:
1327ratelimit - INTEGER 1341ratelimit - INTEGER
1328 Limit the maximal rates for sending ICMPv6 packets. 1342 Limit the maximal rates for sending ICMPv6 packets.
@@ -1514,6 +1528,20 @@ cookie_preserve_enable - BOOLEAN
1514 1528
1515 Default: 1 1529 Default: 1
1516 1530
1531cookie_hmac_alg - STRING
1532 Select the hmac algorithm used when generating the cookie value sent by
1533 a listening sctp socket to a connecting client in the INIT-ACK chunk.
1534 Valid values are:
1535 * md5
1536 * sha1
1537 * none
1538 Ability to assign md5 or sha1 as the selected alg is predicated on the
1539 configuration of those algorithms at build time (CONFIG_CRYPTO_MD5 and
1540 CONFIG_CRYPTO_SHA1).
1541
1542 Default: Dependent on configuration. MD5 if available, else SHA1 if
1543 available, else none.
1544
1517rcvbuf_policy - INTEGER 1545rcvbuf_policy - INTEGER
1518 Determines if the receive buffer is attributed to the socket or to 1546 Determines if the receive buffer is attributed to the socket or to
1519 association. SCTP supports the capability to create multiple 1547 association. SCTP supports the capability to create multiple
@@ -1526,7 +1554,7 @@ rcvbuf_policy - INTEGER
1526 blocking. 1554 blocking.
1527 1555
1528 1: rcvbuf space is per association 1556 1: rcvbuf space is per association
1529 0: recbuf space is per socket 1557 0: rcvbuf space is per socket
1530 1558
1531 Default: 0 1559 Default: 0
1532 1560