Question: I'm getting a lot of messages like these:

```
me@home:/etc/snmp$ tail /var/log/syslog
Jun 12 17:52:15 home nullmailer[1238]: Starting delivery: protocol: smtp host: mail. file: 1339502401.24665
Jun 12 17:52:15 home nullmailer[7086]: smtp: Failed: Connect failed
Jun 12 17:52:15 home nullmailer[1238]: Sending failed:  Host not found
Jun 12 17:52:15 home nullmailer[1238]: Starting delivery: protocol: smtp host: mail. file: 1339174804.27614
Jun 12 17:52:15 home nullmailer[7087]: smtp: Failed: Connect failed
Jun 12 17:52:15 home nullmailer[1238]: Sending failed:  Host not found
Jun 12 17:52:15 home nullmailer[1238]: Starting delivery: protocol: smtp host: mail. file: 1339324201.21737
Jun 12 17:52:15 home nullmailer[7088]: smtp: Failed: Connect failed
Jun 12 17:52:15 home nullmailer[1238]: Sending failed:  Host not found
Jun 12 17:52:15 home nullmailer[1238]: Delivery complete, 331 message(s) remain.

```

The problem is, I don't recall sending anything. How do I find out which software is sending these messages? How do I read them?

Answer: 
To see the contents of one of the messages in the queue, try something like this: (obviously replacing the numeric filename with an actual one from your syslog)

```
$ sudo cat /var/spool/nullmailer/queue/1347323616.6506

```

Note that you have to use either `sudo` or be logged in as root due to permissions on the queue subdir and files.
Might be worth trying

```
sudo apt-get install php5-mcrypt

```

as all the messages being sent were php errors on my system and several other people have reported this as a problem.