Lets say your are unable to connect to a server, and you want to ensure the server is listening on a certain port. Nmap can be used to trace the path to the remote server on a certain port.

nmap -Pn --traceroute -p 443 dns.godaddy.com

Starting Nmap 6.40 ( http://nmap.org ) at 2017-01-02 19:17 CST
Nmap scan report for dns.godaddy.com (104.238.65.158)
Host is up (0.076s latency).
rDNS record for 104.238.65.158: ip-104-238-65-158.ip.secureserver.net
PORT     STATE      SERVICE
443/tcp  filtered   https

TRACEROUTE (using proto 1/icmp)
HOP RTT       ADDRESS
1    4.67 ms  r1.local.com (192.168.0.1)
2   18.84 ms  142.254.152.173
3   35.83 ms  ae62.applwibp02h.midwest.rr.com (24.164.240.217)
4   28.85 ms  be22.gnfdwibb01r.midwest.rr.com (65.31.113.6)
5   30.93 ms  bu-ether16.chcgildt87w-bcr00.tbone.rr.com (66.109.6.204)
6   33.18 ms  bu-ether11.chctilwc00w-bcr00.tbone.rr.com (66.109.6.21)
7   77.75 ms  4.28.83.74
8   69.48 ms  ip-184-168-0-117.ip.secureserver.net (184.168.0.117)
9   83.20 ms  ip-104-238-65-158.ip.secureserver.net (104.238.65.158)