Ytdyklly

I'm just checking the network latency with different tools e.g. with hping3:

sudo hping3 -A -n -p 80 www.google.ro

HPING www.google.ro (ppp0 172.217.20.3): A set, 40 headers + 0 data bytes

len=40 ip=172.217.20.3 ttl=59 id=14578 sport=80 flags=R seq=0 win=0 rtt=23.7 ms

len=40 ip=172.217.20.3 ttl=59 id=60364 sport=80 flags=R seq=1 win=0 rtt=23.2 ms

len=40 ip=172.217.20.3 ttl=59 id=28510 sport=80 flags=R seq=2 win=0 rtt=22.8 ms

len=40 ip=172.217.20.3 ttl=59 id=38493 sport=80 flags=R seq=3 win=0 rtt=22.4 ms

len=40 ip=172.217.20.3 ttl=122 id=35817 sport=80 flags=R seq=4 win=0 rtt=25.7 ms

len=40 ip=172.217.20.3 ttl=122 id=8842 sport=80 flags=R seq=5 win=0 rtt=20.5 ms

^C

--- www.google.ro hping statistic ---

6 packets transmitted, 6 packets received, 0% packet loss

round-trip min/avg/max = 20.5/23.1/25.7 ms

and with ping:

ping www.google.ro

PING www.google.ro (172.217.20.3) 56(84) bytes of data.

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=1 ttl=56 time=16.3 ms

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=2 ttl=56 time=17.1 ms

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=3 ttl=56 time=16.9 ms

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=4 ttl=56 time=16.5 ms

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=5 ttl=56 time=16.3 ms

64 bytes from bud02s28-in-f3.1e100.net (172.217.20.3): icmp_seq=6 ttl=56 time=16.3 ms

^C

--- www.google.ro ping statistics ---

6 packets transmitted, 6 received, 0% packet loss, time 5007ms

rtt min/avg/max/mdev = 16.365/16.613/17.105/0.341 ms

After a few series with these 2 commands I noticed that hping3 is always reporting a higher latency than ping. Why this happens and how could one fix it?

PS: using Ubuntu 16.04.5 LTS (directly connected to Internet) and UFW (ver. 0.35)

You're not seeing the same test run with different tools. hping3 is running a "ping" using the TCP protocol on port 80; ping is running an ICMP echo request which is a different test entirely.

ICMP is IP protocol 1 (see RFC792); TCP is IP protocol 6 (described in RFC793). TCP (as does UDP) has ports, ICMP has no ports, but rather types and codes.

In general, an ICMP echo request is going to be a "lighter lift" because it's a "lighter weight" protocol (e. g. addressing not needing to specify source or endpoint ports) which means that, all things being equal, it is more likely than not to have a shorter response time due to fewer processing requirements than a comparable TCP packet.

The size of the packet header alone for an ICMP packet is 52 bytes (24, 20, and 8 bytes each for Ethernet, IP, and ICMP respectively), while the size of the packet header alone for a TCP packet is 64 btyes (24, 20, and 20 bytes each for Ethernet, IP, and TCP respectively).