Limit Bandwidth Usage in Lighttpd

Starting with version 1.3.8, lighttpd supports limiting the bandwidth for a single connection or config context like a virtual host or a URL

connection.kbytes-per-second:

limit the throughput for each single connection to the given limit in kbyte/s

default: 0 (no limit)

server.kbytes-per-second:

limit the throughput for all connections to the given limit in kbyte/s

if you want to specify a limit for a special virtual server use:

$HTTP["host"] == "www.example.org" {
server.kbytes-per-second = 128
}

which will override the default for this host.

default: 0 (no limit)

Additional Notes

Keep in mind that a limit below 32kb/s might actually limit the traffic to 32kb/s. This is caused by the size of the TCP send buffer.

More info