[[meta title="Advanced usage of the Monkeysphere"]] Advanced usage of the monkeysphere ================================== Keeping your `known_hosts` file in sync with your keyring --------------------------------------------------------- If you want to keep your keyring updated without attempting connections to a remote host, you want to make sure that OpenSSH can still see the most recent trusted information about who the various hosts are. You might also want to check on hosts that were not originally in the Monkeysphere, to see if their host key is now published. You can do this kind of independent update with the `update-known_hosts` command: $ monkeysphere update-known_hosts This command will check to see if there is an OpenPGP key for each (non-hashed) host listed in the `known_hosts` file, and then add the key for that host to the `known_hosts` file if one is found. This command could be added to a crontab, if desired. Establishing trust ------------------ The Monkeysphere is predicated on the idea that users and administrators know each other (or know people who know each other, etc). It uses the Web of Trust to explicitly represent those links. If you haven't used the Web of Trust explicitly, you will need to establish an acceptable trust path to the admin(s) of the monkeysphere-enabled servers that you will be connecting to. You need to do this because the admin is certifying the host, and you need a mechanism to validate that certification. The only way to do that is by indicating who you trust to certify hosts. This is a two step process: first you must sign the key, and then you have to indicate a trust level. If you do not indicate that you trust the administrator to certify host keys, then the monkeysphere will show you her certification on every connection, but will not treat it as an automatic verification. The process of signing another key is outside the scope of this document, however the [gnupg README](http://cvs.gnupg.org/cgi-bin/viewcvs.cgi/branches/STABLE-BRANCH-1-4/README?root=GnuPG&view=markup) details the signing process and you can find good [documentation ](http://www.debian.org/events/keysigning) online detailing this process. If you have signed your admins' key, you need to denote some kind of trust to that key. To do this you should edit the key and use the 'trust' command. For the Monkeysphere to trust the assertions that are made about a host, you need full calculated validity to the host certifiers. This can be done either by giving full trust to one host-certifying key, or by giving marginal trust to three different host-certifiers. In the following we demonstrate how to add full trust validity to a host-certifying key: $ gpg --edit-key 'Jane Admin' gpg (GnuPG) 1.4.9; Copyright (C) 2008 Free Software Foundation, Inc. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. pub 4096R/ABCD123A created: 2007-06-02 expires: 2012-05-31 usage: SC trust: unknown validity: full sub 2048R/01DECAF7 created: 2007-06-02 expires: 2012-05-31 usage: E [ full ] (1). Jane Admin Command> trust pub 4096R/ABCD123A created: 2007-06-02 expires: 2012-05-31 usage: SC trust: unknown validity: full sub 2048R/01DECAF7 created: 2007-06-02 expires: 2012-05-31 usage: E [ full ] (1). Jane Admin Please decide how far you trust this user to correctly verify other users' keys (by looking at passports, checking fingerprints from different sources, etc.) 1 = I don't know or won't say 2 = I do NOT trust 3 = I trust marginally 4 = I trust fully 5 = I trust ultimately m = back to the main menu Your decision? 4 pub 4096R/ABCD123A created: 2007-06-02 expires: 2012-05-31 usage: SC trust: full validity: full sub 2048R/01DECAF7 created: 2007-06-02 expires: 2012-05-31 usage: E [ full ] (1). Jane Admin Please note that the shown key validity is not necessarily correct unless you restart the program. Command> save Key not changed so no update needed. $ Note: Due to a limitation with gnupg, it is not currently possible to limit the domain scope properly, which means that if you fully trust an admin, you'll trust all their certifications. Because the Monkeysphere currently relies on GPG's definition of the OpenPGP web of trust, it is important to understand [how GPG calculates User ID validity for a key](/trust-models). Miscellaneous ------------- Users can also maintain their own `~/.ssh/authorized_keys` files with the Monkeysphere directly. This is primarily useful for accounts on hosts that are not already systematically using the Monkeysphere for user authentication. If you're not sure whether this is the case for your host, ask your system administrator. If you want to do this as a regular user, use the `update-authorized_keys` command: $ monkeysphere update-authorized_keys This command will take all the user IDs listed in the `~/.monkeysphere/authorized_user_ids` file and check to see if there are acceptable keys for those user IDs available. If so, they will be added to the `~/.ssh/authorized_keys` file. You must have indicated reasonable ownertrust in some key for this account, or no keys will be found with trusted certification paths. If you find this useful, you might want to place this command in your crontab so that revocations and rekeyings can take place automatically.