In a case I can use only
ICMP protocols, how can I discover, in bytes, the path MTU for packet transfer from my computer to a destination IP?
I believe what you are looking for, is easiest gotten via
traceroute --mtu <target>; maybe with a
-6 switch thrown in for good measure depending on your interests.
traceroute uses UDP as a default, if you believe your luck is better with ICMP try also
A quick search with
apropos mtu on CentOS5 turned out:
tracepath traces path to a network host discovering MTU along this path
This command even works unprivileged in user space.