Check the tcp stack settings:

cat /proc/sys/net/ipv4/tcp_window_scaling (on by default)

cat /proc/sys/net/core/{r,w}mem_default

cat /proc/sys/net/core/{r,w}mem_max

cat /proc/sys/net/ipv4/tcp_{r,w}mem

NIC MTU

ifconfig <device> mtu 9000

netperf

Default port for netserver is 12865/tcp

Run an ipv4 daemon server side on tcp 1080:

netserver -4 -L <ip_addr>

connect to the server from a client using:

netperf -H <server_ip> -t TCP_STREAM -C -c -l 60
netperf -H <server_ip> -t TCP_SENDFILE -C -c -l 60 -F /usr/share/man/man1/netperf.1.gz
netperf -H <server_ip> -t UDP_STREAM -C -c -l 60 -m 8972 -s 4M -S 4M