Sysctl variable	Default 2.6	Suggested
net.ipv4.conf.all.arp_filter	0	1
net.ipv4.conf.all.rp_filter	0	1
net.ipv4.tcp_max_syn_backlog	1024	4096
net.ipv4.ipfrag_low_thresh	196608	262144
net.ipv4.ipfrag_high_thresh	262144	393216
net.core.netdev_max_backlog	300	2000
net.core.rmem_default	135168	262144
net.core.rmem_max	131071	8388608
net.core.wmem_default	135168	262144
net.core.wmem_max	131071	8388608
net.ipv4.ip_local_port_range	32768 61000	1024 65535
net.ipv4.ip_no_pmtu_disc	0	0
net.ipv4.tcp_rmem	4096 87380 174760	8192 262144 4194304
net.ipv4.tcp_sack	1	0
net.ipv4.tcp_syncookies	1	0
net.ipv4.tcp_timestamps	1	0
net.ipv4.tcp_window_scaling	1	1
net.ipv4.tcp_wmem	4096 16384 131072	8192 262144 4194304

---

$ sysctl -w net.ipv4.conf.all.arp_filter=1
$ sysctl -w net.ipv4.conf.all.rp_filter=1
$ sysctl -w net.ipv4.tcp_max_syn_backlog=4096
$ sysctl -w net.ipv4.ipfrag_low_thresh=262144
$ sysctl -w net.ipv4.ipfrag_high_thresh=393216
$ sysctl -w net.core.netdev_max_backlog=2000
$ sysctl -w net.core.rmem_default=262144
$ sysctl -w net.core.rmem_max=8388608
$ sysctl -w net.core.wmem_default=262144
$ sysctl -w net.core.wmem_max=8388608
$ sysctl -w net.ipv4.ip_local_port_range="1024 65535"
$ sysctl -w net.ipv4.ip_no_pmtu_disc=0
$ sysctl -w net.ipv4.tcp_rmem="8192 262144 4194304"
$ sysctl -w net.ipv4.tcp_sack=0
$ sysctl -w net.ipv4.tcp_syncookies=0
$ sysctl -w net.ipv4.tcp_timestamps=0
$ sysctl -w net.ipv4.tcp_window_scaling=1
$ sysctl -w net.ipv4.tcp_wmem="8192 262144 4194304"