0. Meta-info

• Where can I get this document?
• Who maintains this document?
• Where do I send questions, additions, corrections etc. about this document?
• Revision history.
• Legalese.
• Credits.
• Related Web pages.

1. About stunnel

• What is stunnel?
• What encryption algorithms does stunnel use?
• What forms of authentication does stunnel use?
• What forms of authentication does stunnel support?
• What does stunnel protect against?
• What doesn't stunnel protect against?
• Who maintains stunnel?
• Can I run stunnel legally?
• Licensing.
• Cryptography laws.
• Patents on Cryptographic algorithms.
• What operating systems does stunnel run on?

2. Getting stunnel

• What is the latest release of stunnel?
• Where is the official stunnel distribution and mirror sites?

3. Installing stunnel

• How do I use the pre-compiled windows binaries?
• How do I compile stunnel from sources?
• Configure options.

4. Running stunnel

• Running stunnel in inetd mode .
• Running stunnel in daemon mode.
• Running stunnel with tcp wrappers.
• Stopping stunnel.

5. Stunnel arguments

• Important note.
• Stunnel command line arguments.

6. Examples of running stunnel

• Setting up PPP over stunnel (Make your own VPN).
• Examples of launching programs from an stunnel daemon.
• Examples of encrypting existing services.
• Examples of tcp wrapper service names for stunnel.
• Forwarding an insecure port securely from one machine to another.

7. Stunnel and other applications

• Can I forward UDP services over stunnel?
• Can I use stunnel to communicate across a firewall?
• Can I use stunnel to securely connect two subnets across the Internet?
• Can I use stunnel to protect [insert random protocol here]?

8. Troubleshooting

• Common Compilation Problems
  • Couldn't find your SSL library installation dir.
  • I get an error about PEM_read_bio_DHparams.
  • Configure can't find my ssl directories.
  • Configure can't find my tcp wrapper installation.
• Problems running stunnel
  • Hints for debugging.
  • SSL_accept: error:00000000::lib(0) :func(0) :reason(0)
  • I can't get ftp to work.
  • Stunnel isn't working with Window 2000 (Outlook Express).
  • I can't type anything when running stunnel in client mode on Windows.
  • Stunnel doesn't seem to be reusing session IDs in client mode.
  • Why do I get a "PRNG not seeded" error message?

9. Getting support for stunnel

• The stunnel mailing list.
• The stunnel mailing list archives.

A. Using certificates with stunnel

• Quick certificate overview.
• What's a certificate?
• Do I need a valid certificate?
• Generating the stunnel private key (pem).
• Problems with a self-signed certificate.
• Do I need to have a Certificate Authority sign my key?
• How can I have my key signed by a CA?
• Can I set up my own CA instead?
• How does stunnel check certificates?
• Where do I put all these certificates?

B. Miscellany

• What are the official SSL ports?