> Instead, the TCP 3-way handshake won't complete (the syn-ack is dropped).
Sounds like my internet connection in grad student housing about 10% of the time, except the initial SYN is dropped. Pings and everything else are fine.
I remember one guy in my company had hard-on on blocking every way to tunnel out of our network (...that was not required by anyone, he was just security nut).
We had sites blacking out because he decided DNS tunnelling bad so he blocked anything with low TTL. Meanwhile simple POC DNS tunnel worked fine..
Sounds like my internet connection in grad student housing about 10% of the time, except the initial SYN is dropped. Pings and everything else are fine.