I travel a lot, and frequently find myself on a poorly-configured “guest” network which blocks all kinds of connections, sometimes including my VPN. I'm setting up an alternative tunneling configuration, but I want to pick ports which are least likely to be blocked outright. Which ports am I most likely to be able to use reliably among crummy captive portals and so on?

  • I'm aware that this isn't going to evade a cunning censor, but that's not my threat model.
    – flamsmark
    Dec 16 '13 at 0:02
  • Guest networks that block access to ports aren't poorly configured, they are correctly set up in most cases. Guest networks are generally designed to offer minimal access because there is no model of trust to base access on. While http and https are likely to be open, they are also likely to be inspected for conformity to the protocol - you can't just put whatever you like over them. You need an https based VPN.
    – Paul
    Dec 16 '13 at 0:22

443 is your best bet. It takes special client configuration to tolerate having port 443 blocked, so it's almost never blocked.

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