root@r:~# wget -4 -O /dev/null http://speedtest.dal05.softlayer.com/downloads/test100.zip
--2016-01-12 04:43:37--  http://speedtest.dal05.softlayer.com/downloads/test100.zip
Resolving speedtest.dal05.softlayer.com (speedtest.dal05.softlayer.com)... 173.192.68.18
Connecting to speedtest.dal05.softlayer.com (speedtest.dal05.softlayer.com)|173.192.68.18|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 104874307 (100M) [application/zip]
Saving to: ‘/dev/null’

/dev/null                                  100%[==========================================================================================>] 100.02M  5.55MB/s   in 28s

2016-01-12 04:44:05 (3.62 MB/s) - ‘/dev/null’ saved [104874307/104874307]

root@r:~# wget -6 -O /dev/null http://speedtest.dal05.softlayer.com/downloads/test100.zip
--2016-01-12 04:44:06--  http://speedtest.dal05.softlayer.com/downloads/test100.zip
Resolving speedtest.dal05.softlayer.com (speedtest.dal05.softlayer.com)... 2607:f0d0:1101:4::2
Connecting to speedtest.dal05.softlayer.com (speedtest.dal05.softlayer.com)|2607:f0d0:1101:4::2|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 104874307 (100M) [application/zip]
Saving to: ‘/dev/null’

/dev/null                                  100%[==========================================================================================>] 100.02M  29.8MB/s   in 5.8s

2016-01-12 04:44:13 (17.3 MB/s) - ‘/dev/null’ saved [104874307/104874307]

root@r:~# wget -O /dev/null http://mirror.nl.leaseweb.net/speedtest/100mb.bin -4
--2016-01-12 04:46:06--  http://mirror.nl.leaseweb.net/speedtest/100mb.bin
Resolving mirror.nl.leaseweb.net (mirror.nl.leaseweb.net)... 94.75.223.121
Connecting to mirror.nl.leaseweb.net (mirror.nl.leaseweb.net)|94.75.223.121|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 100000000 (95M) [application/octet-stream]
Saving to: ‘/dev/null’

/dev/null                                  100%[==========================================================================================>]  95.37M  5.89MB/s   in 19s

2016-01-12 04:46:26 (4.90 MB/s) - ‘/dev/null’ saved [100000000/100000000]

root@r:~# wget -O /dev/null http://mirror.nl.leaseweb.net/speedtest/100mb.bin -6
--2016-01-12 04:46:30--  http://mirror.nl.leaseweb.net/speedtest/100mb.bin
Resolving mirror.nl.leaseweb.net (mirror.nl.leaseweb.net)... 2001:1af8:4030:1:0:dead:beef:cafe
Connecting to mirror.nl.leaseweb.net (mirror.nl.leaseweb.net)|2001:1af8:4030:1:0:dead:beef:cafe|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 100000000 (95M) [application/octet-stream]
Saving to: ‘/dev/null’

/dev/null                                  100%[==========================================================================================>]  95.37M  57.8MB/s   in 1.6s

2016-01-12 04:46:32 (57.8 MB/s) - ‘/dev/null’ saved [100000000/100000000]