In part 1 I outlined the many problems caused by wifi login pages that hijack your browser ("captive portals") and how to improve things.
Today I want to discuss the sad state of having security in WIFI in most of the setups used today.
Almost all open WIFI networks are simply "in the clear." That means, however you got on, your traffic is readable by anybody, and can be interfered with as well, since random users near you can inject fake packets or pretend to be the access point. Any security you have on such a network depends on securing your outdoing connections. The most secure way to do this is to have a VPN (virtual private network) and many corporations run these and insist their employees use them. VPNs do several things:
- Encrypt your traffic
- Send all the traffic through the same proxy, so sniffers can't even see who else you are talking to
- Put you on the "inside" of corporate networks, behind firewalls. (This has its own risks.)
VPNs have downsides. They are hard to set up. If you are not using a corporate VPN, and want a decent one, you typically have to pay a 3rd party provider at least $50/year. If your VPN router is not in the same geographic region as you are, all your traffic is sent to somewhere remote first, adding latency and in some cases reducing bandwidth. Doing voice or video calls over a VPN can be quite impractical -- some VPNs are all TCP without the UDP needed for that, and extra latency is always a killer. Also, there is the risk your VPN provider could be snooping on you -- it actually can make it much easier to snoop on you (by tapping the outbound pipe of your VPN provider) than to follow you everywhere to tap where you are.
If you don't have a VPN, you want to try to use encrypted protocols for all you do. At a minimum, if you use POP/IMAP E-mail, it should be configured to only get and receive mail over TLS encrypted channels. In fact, my own IMAP server doesn't even accept connections in the clear to make sure nobody is tempted to use one. For your web traffic, use sites in https mode as much as possible, and use EFF's plugin https everywhere to make your browser switch to https wherever it can.