Has anyone ever found a tool that performs a TCP traceroute with an actual established TCP session? I can launch a server/client on each end, if required. tcptraceroute & mtr aren't candidates here. (The docs for tcptraceroute state, "It is worth noting that tcptraceroute never completely establishes a TCP connection with the destination host.")
In my case, TCP traceroutes w/mtr are not showing any packet loss or congestion along the path, but actual sessions between iperf3 server & client do show congestion on the path between server & client on some sessions where the TCP packets are more substantial than simple SYN packets.
My theory is that a path in the middle is operating at the TCP layer and is load balanced. I'm guessing that individual TCP sessions are pinned to a single device during their lifetime. If I could use a tool that would establish a real connection and then incrementally change the TTL on the IP packet headers (without manipulating the TCP headers), I could determine if sessions really pinned somewhere in the middle and potentially which device in the middle is responsible for congestion issues.