On Sun, 2008-10-05 at 18:00 +0000, Beartooth wrote: > FATAL: Could not determine fully qualified hostname. Please set > 'visible_hostname' > > > I don't know what a qualified hostname is, fully or not. There's plenty of places on the WWW that explain that, but here goes. A "hostname" is the (generally) one-word name that you address your machine by (the name associated with a numerical IP address). e.g. localhost is the hostname associated with 127.0.0.1 - the local loopback address (internal networking that doesn't leave the PC). The same applies for associating a hostname with an IP address that can be connected to from another PC on the network. e.g. This PC is called gonzales (since it was the fastest box on the LAN), I set that as its hostname, and it's IP address is 192.168.1.11. A fully-qualified domain name (FQDN) is the complete address, hostname plus the domain name. e.g. www.example.com. Strictly speaking, it ends with a dot (representing the top of the tree), though few people see that unless they're working with domain name servers. The dot means that it's the full address, otherwise its (probably) a hostname, and the system will try and work out what domain name should be appended to it, to turn it into a FQDN. The process of working it out *CAN* be done like this. I am "gonzales" lookup this to find my IP, I find I am 192.168.1.11. Okay, now lets lookup 192.168.1.11 (a reverse lookup) to find my FQDN, and I get told that I'm "gonzales.example.com.", and that's the end of that story. However, if I'd queried 192.168.1.11 and been told that I'm "gonzales.lan" (note the lack of a trailing dot), I'd know that's not a FQDN, just a hostname (albeit one with a dot in it), so I'd go through the query cycle again - find the IP for gonzales.lan, then find the address associated with that IP, hopefully getting a FQDN. This sort of thing can be a bit of a pain when someone sets up machines with multiple names, that need to be stepped through to work out the FQDN. And this set of resolution steps (find the IP, find the name, rinse, lather, repeat) is the process SSH goes through before allowing a connection (checking that names and IPs match, in both directions). ALTERNATIVELY: Your network can be configured to prepend specific domain names to hostnames. So if a hostname is used (a name that doesn't *END* with a dot), it automatically prepends the preferred domain name to it. See the "domain" and "search" parameters that are used in the /etc/resolv.conf (man resolv.conf). Basically "domain" means providing one answer for a domain that you are part of, whereas "search" allows you to give a list of domain names to try. e.g. If I had example.com and example.net as search parameters, and I did "ping www", my system would first see if it found an answer (finds an IP address) for just "www", then "www.example.com", then "www.example.net", in turn. The first answer wins. There's also configuration options for what constitutes the domain name if there's multiple dots in it. e.g. Given "mail.lan.example.com", the domain could be lan.example.com or it could be example.com. You can configure whether the domain starts after the first dot, or after how many dots. The dividing line between what you consider to be a domain, or a sub-domain, is up to how you want your network configuration. In the simple case, the /etc/hosts file is used for resolving names, but that involves putting the same hosts file on each machine on the network. I use a DNS server, which serves the same purpose, but on one central server. -- [tim@localhost ~]$ uname -r 2.6.26.5-45.fc9.i686 Don't send private replies to my address, the mailbox is ignored. I read messages from the public lists. -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
