Repository key not available
Keys sometimes expire!
Err:2 http://ftp.it.debian.org/debian testing InRelease
Le seguenti firme non sono state verificate perché la chiave pubblica non è disponibile: NO_PUBKEY 9D6D8F6BC857C906
With Debian, it's possible to get a new key just using the command
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys KEY_SIG
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9D6D8F6BC857C906
Cannot upgrade or remove a very old package?
Use the commands:
cd /var/cache/apt/archives #to enter the directory with all deb archives
dpkg -D777 -r ARCHIVENAME #to remove a package, with debug information
dpkg -D777 -i ARCHIVENAME-version-arch.deb #to install it
With these commands you can know exactly where is the problem. Often, the info file for the old archive does not longer exist, so you have to edit the script file (for example /var/lib/dpkg/info/coreutils.prerm ) adding || true to bypass the error (for example install-info --remove INFOFILE || true )
Postfix + Amavis + Spamassassin + Dovecot
Is postfix very slow to process a huge mail queue?
- Check that virus scanning is not too slow. If it's slow, don't use clamscan (very slow) but prefer clamdscan (clamav-daemon): it requires a lots of memory but it's much more faster than clamscan!
- You can also increase max_servers value on /usr/sbin/amavisd-new to get more than 2 processes for mail scanning (then, increase local smptd on port 10025 or similar, in /etc/postfix/main.cf)