W: GPG error: http://volatile.debian.org lenny/volatile Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY DFD993306D849617
Use the key id that is complaining
root@bt:/etc/apt# gpg --keyserver wwwkeys.eu.pgp.net --recv-keys DFD993306D849617
gpg: directory `/root/.gnupg' created
gpg: new configuration file `/root/.gnupg/gpg.conf' created
gpg: WARNING: options in `/root/.gnupg/gpg.conf' are not yet active during this run
gpg: keyring `/root/.gnupg/secring.gpg' created
gpg: keyring `/root/.gnupg/pubring.gpg' created
gpg: requesting key 6D849617 from hkp server wwwkeys.eu.pgp.net
gpgkeys: HTTP fetch error 6: Couldn't resolve host 'wwwkeys.eu.pgp.net'
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0
root@bt:/etc/apt# gpg --keyserver wwwkeys.uk.pgp.net --recv-keys DFD993306D849617
gpg: requesting key 6D849617 from hkp server wwwkeys.uk.pgp.net
gpg: /root/.gnupg/trustdb.gpg: trustdb created
gpg: key 6D849617: public key "Debian-Volatile Archive Automatic Signing Key (5.0/lenny)" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
root@bt:/etc/apt# gpg --armor --export DFD993306D849617 | apt-key add -
OK
