Installing and Administering Internet Services

160 Chapter 4
Installing and Administering sendmail
Troubleshooting sendmail
the same process ID. sendmail starts with TAA and loops through TAB,
TAC, and so on, until it is able to form a unique ID. The five-digit number
(nnnnn) is the process ID of the process creating the queue entry.
A file whose name begins with df is a data file. The message body,
excluding the header, is kept in this file.
A file whose name begins with qf is a queue-control file, which contains
the information necessary to process the job.
A file whose name begins with xf is a transcript file. This file is normally
empty while a piece of mail is in the queue. If a failure occurs, a
transcript of the failed mail transaction is generated in this file.
The queue-control file (type qf) is structured as a series of lines, each
beginning with a letter that defines the content of the line. Lines in
queue-control files are described in Table 4-4.
Table 4-4 Lines in Queue-Control Files
Initial
Letter
Content of Line
B The message body type (either 7bit or 8bitmime).
C The controlling user for message delivery. This line always precedes a
recipient line (R) that specifies the name of a file or program name. This line
contains the user name that sendmail should run as when it is delivering a
message into a file or a program’s stdin.
D The name of the data file. There can be only one D line in the queue-control
file.
E An error address. If any such lines exist, they represent the addresses that
should receive error messages.
H A header definition. There can be many H lines in the queue-control file.
Header definitions follow the header definition syntax in the configuration
file.
P The current message priority. This is used to order the queue. Higher
numbers mean lower priorities. The priority decreases (that is, the number
grows) as the message sits in the queue. The initial priority depends on the
message precedence, the number of recipients, and the size of the message.