How to setup caff and exim to work on Fedora 16

Exim configuration

• We need to install exim and system-switch-mail:

$ sudo yum install exim system-switch-mail

• Use system-switch-mail to set Exim as the default MTA used by the system:

$ sudo system-switch-mail

• Configure Exim to deliver emails through your ISP smtp server by editing the file /etc/exim/exim.conf

• In the ROUTERS CONFIGURATION, find and put in comment the following line, like this:

#dnslookup:
#  driver = dnslookup
#  domains = ! +local_domains
#  transport = remote_smtp
#  ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
#  no_more

• Find or add the following line just below the commented dnslookup: instance:

smarthost:
  driver = manualroute
  domains = ! +local_domains
  transport = remote_smtp
  route_data = <your_isp_smtp_server_hostname_here>
  no_more

• ALTERNATIVELY you can configure exim to use an SSH tunnelled smtp server.

• For instance 127.0.2.1:10025 is redirected to smtp.domain.com:25 with:

$ ssh -fN -L127.0.2.1:10025:smtp.domain.com:25 user@server.domain.com

• You must then add a new transport instance with specification of the smarthost port (10025 in our example). In the ROUTERS CONFIGURATION, add a new router as follows:

remote_tun_smtp:
  driver = smtp
  port = 10025

• Adapt the smarthost: instance to use the new transport instance (called remote_tun_smtp in our example) and the local address used for the redirection (127.0.2.1 in our example):

smarthost:
  driver = manualroute
  domains = ! +local_domains
  transport = remote_tun_smtp
  route_data = 127.0.2.1
  no_more

• Finally, make it possible for your user to use the exim -r option (equivalent to sendmail -f option). Edit /etc/exim/exim.conf and add under the MAIN CONFIGURATION section the line:

trusted_users = <you_username_here>:root:exim

Now (re)start exim:

$ sudo service exim stop; sleep 5; sudo service exim start

To make exim start upon reboots:

$ sudo chkconfig --add exim

caff configuration

• Install caff utility. caff is provided by the package pgp-tools:

$ sudo yum install pgp-tools

• Configure caff by editing your ~/.caffrc file as follows:

$CONFIG{'owner'} = 'Firstname Lastname';
$CONFIG{'email'} = 'user@domain.tld';
$CONFIG{'reply-to'} = 'user@domain.tld';
$CONFIG{'mailer-send'} =  [ 'sendmail', '-f user@domain.tld' ];
$CONFIG{'keyid'} = [ qw{<HERE_16_DIGITS_OF_YOUR_PGP_KEY>} ];

• Now you can start signing PGP keys with:

caff --no-download --key-file <file_containing_exported_keys> <key_ID1> <key_ID2> <key_ID3> ...

and check that emails are correctly sent by inspecting the file /var/log/exim/main.log