man traceroute
traceroute tracks the route packets take across an IP network on their way to a given host. It utilizes the IP protocol’s time to live (TTL) field and attempts to elicit an ICMP TIME_EXCEEDED response from each gate-way along the path to the host.
-T Use TCP SYN for probes
使用例
# traceroute xxx.xxx.xxx.xxx -T -p 22
通信経路の確認はTCP(デフォルトはUDP)にしつつ、ポートは22番を指定している。