For about 15 years beginning in 2003 I had some VPSs with CrystalTech/NewTek. I noticed right away that they had blocked all port 23 traffic in/out of their edge.

I asked them about it and they said it was a security measure. Apparently they used telnet for managing their routers.

It turned out that they did not have very good security anyway.

https://krebsonsecurity.com/2018/02/domain-theft-strands-tho...

I switched to A2 hosting shortly after the above incident, but I dumped them when they did not keep up to date on their Ubuntu LTS OS options.

I've been running on AWS for the past eight years. It costs more, but it's been extraordinarily reliable.

A2 and AWS do not restrict port 23.