To see which ports a process opens, you can use strace like this:
$ strace -f -e trace=network -s 10000 \
git ls-remote -h -t git://github.com/fengyuanchen/datepicker.git 2>&1 | \
grep -w connect | \
grep -v NOENT
connect(3, {sa_family=AF_INET, sin_port=htons(9418), sin_addr=inet_addr("192.30.253.113")}, 16) = 0
connect(3, {sa_family=AF_UNSPEC, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16) = 0
connect(3, {sa_family=AF_INET, sin_port=htons(9418), sin_addr=inet_addr("192.30.253.112")}, 16) = 0
connect(3, {sa_family=AF_INET, sin_port=htons(9418), sin_addr=inet_addr("192.30.253.113")}, 16) = 0
The above command figures out which servers and ports the command git
ls-remote -h -t git://github.com/fengyuanchen/datepicker.git will
attempt to open. As you can see, using git over the git:// protocol
will access the git server, github.com in this case, on port 9418.
strace is awesome, yeah?
sherlock
Admittedly, the above is a mouthful to type, so I've written a command called sherlock which makes this easy and presents the output on a more human friendly format:
$ sherlock git ls-remote -h -t git://github.com/fengyuanchen/datepicker.git
192.168.1.53:53 dns.example.com:53
192.30.253.113:443 lb-192-30-253-113-iad.github.com:443
192.30.253.112:443 lb-192-30-253-112-iad.github.com:443
192.30.253.113:443 lb-192-30-253-113-iad.github.com:443
