Sto cercando di ottimizzare le prestazioni di Snort su un router basato su Debian. Stavo vedendo cose come:
snort packet recv contents failure: No buffer space available
Quindi ho aumentato i buffer a 8M e quando non ha funzionato ho provato 16M, secondo la guida alla messa a punto su http://fasterdata.es.net/fasterdata/host-tuning/linux/ :
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
# Increase TCP Buffers to 16 MB
sysctl -w net.core.rmem_default='16777216'
sysctl -w net.core.wmem_default='16777216'
sysctl -w net.core.rmem_max='16777216'
sysctl -w net.core.wmem_max='16777216'
sysctl -w net.ipv4.tcp_wmem='1048576 4194304 16777216'
sysctl -w net.ipv4.tcp_rmem='1048576 4194304 16777216'
sysctl -w net.core.netdev_max_backlog='30000'
exit 0
Ora non vedo la voce di registro "nessuno spazio buffer", ma ne ho una nuova:
net_ratelimit: 44 callbacks suppressed
Gli unici altri messaggi dello stesso lasso di tempo sono questi marziani, forse è quello che viene soppresso?
Jun 4 07:09:36 ilium ntpd_intres[3575]: host name not found: 0.us.pool.ntp.org
Jun 4 14:17:36 ilium kernel: [25743.259951] net_ratelimit: 44 callbacks suppressed
Jun 4 14:17:36 ilium kernel: [25743.259955] martian source 216.59.11.21 from 127.0.0.1, on dev eth0
Jun 4 14:17:36 ilium kernel: [25743.259956] ll header: 00:30:48:7c:f8:10:00:24:c4:49:8d:00:08:00
Jun 4 14:17:58 ilium kernel: [25765.055449] martian source 216.59.11.21 from 127.0.0.1, on dev eth0
Jun 4 14:17:58 ilium kernel: [25765.055451] ll header: 00:30:48:7c:f8:10:00:24:c4:49:8d:00:08:00
Jun 4 14:18:43 ilium kernel: [25809.998978] martian source 216.59.11.21 from 127.0.0.1, on dev eth0
Jun 4 14:18:43 ilium kernel: [25809.998980] ll header: 00:30:48:7c:f8:10:00:24:c4:49:8d:00:08:00
Jun 4 14:24:11 ilium kernel: [26138.700143] martian source 216.59.11.71 from 127.0.0.1, on dev eth0
Jun 4 14:24:11 ilium kernel: [26138.700145] ll header: 00:30:48:7c:f8:10:00:24:c4:49:8d:00:08:00
Jun 4 14:28:42 ilium kernel: [26409.130701] martian source 216.59.11.71 from 127.0.0.1, on dev eth0
Jun 4 14:28:42 ilium kernel: [26409.130703] ll header: 00:30:48:7c:f8:10:00:24:c4:49:8d:00:08:00
__ratelimit: # callbacks supressed