linux上更改TCP窗口大小

使用route命令。像ifconfig, route, ip等这些工具参数非常多，有问题时应该看看这些工具的参数。窗口大小的变动对FTP等程序性能影响很明显。

[root@jcwkyl ipv4]# route del -net 10.60.56.0/24
[root@jcwkyl ipv4]# route add -net 10.60.56.0/24 window 4096 dev eth0
[root@jcwkyl ipv4]# route -n
Kernel IP routing table
Destination    Gateway        Genmask         Flags MetricRef    Use Iface
10.60.56.0     0.0.0.0        255.255.255.0   U    0     0        0 eth0
169.254.0.0    0.0.0.0        255.255.0.0     U    0     0        0 eth0
0.0.0.0        10.60.56.254   0.0.0.0        UG    0     0        0 eth0
[root@jcwkyl ipv4]# netstat -r
Kernel IP routing table
Destination    Gateway        Genmask        Flags   MSS Window  irtt Iface
10.60.56.0     *              255.255.255.0  U         04096       0 eth0
169.254.0.0    *              255.255.0.0    U         00          0 eth0
default        10.60.56.254   0.0.0.0        UG        00          0 eth0

[root@jcwkyl ipv4]# route del default gw 10.60.56.254
[root@jcwkyl ipv4]# route add default gw 10.60.56.254 window 4096 dev eth0
[root@jcwkyl ipv4]# route -n
Kernel IP routing table
Destination    Gateway        Genmask         Flags MetricRef    Use Iface
10.60.56.0     0.0.0.0        255.255.255.0   U    0     0        0 eth0
169.254.0.0    0.0.0.0        255.255.0.0     U    0     0        0 eth0
0.0.0.0        10.60.56.254   0.0.0.0        UG    0     0        0 eth0
[root@jcwkyl ipv4]# netstat -r
Kernel IP routing table
Destination    Gateway        Genmask        Flags   MSS Window  irtt Iface
10.60.56.0     *              255.255.255.0  U         04096       0 eth0
169.254.0.0    *              255.255.0.0    U         00          0 eth0
default        10.60.56.254   0.0.0.0        UG        04096       0 eth0


还需要关掉scalable，即：
[root@jcwkyl ipv4]# echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

如果希望这个更改在重启后也生效，可以将下面这一行添加到/etc/sysctl.conf文件中：
net.ipv4.tcp_window_scaling=0