linux

1. What change is necessary to make sendmail listen to all network traffic on port 25? What file would you edit?
This server does not relay outbound email originating on other systems. For this configuration to work, you must be able to make outbound connections from and receive inbound connections to port 25. The line in sendmail.mc that limits sendmail to accepting inbound email from the local system only isDAEMON_OPTIONS(‘Port=smtp,Addr=127.0.0.1, Name=MTA') dnlTo allow sendmail to accept inbound email from other systems, remove the parameter Addr=127.0.0.1, from the preceding line:DAEMON_OPTIONS(‘Port=smtp, Name=MTA')dnl By default, sendmail does not use a remote SMTP server to relay email, so there is nothing to change to cause sendmail to send email directly to recipients’ systems.

2. What two files does sendmail create while processing a message?
The daemon stores the body of the message in a file named df(data file) followed by the generated string. It stores the headers and other information in a file named qf (queue file) followed by the generated string.

3. What does dnl stand for in the m4 macro language? What are dnl commands used for?

The dnl command, which stands for delete to new line, instructs the compiler to ignore anything on a line following the dnl. It is used to set off
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4. How can you use praliases to regenerate a host alias file?
You can use praliases to list aliases currently loaded by sendmail

5. In what file do you setup relaying for sendmail?

The sendmail init script regenerates access.db from access each time you run it, as when you restart sendmail.

6. List the purpose of each of the following SMTP commands?
a. HELO: begins the session and identifies the local system

b. RCPT TO: Specifies the e-mail address of the recipient. This command can be repeated multiple times for a given e-mail message in order to deliver a single e-mail message to multiple recipients

c. DATA: starts the transfer of the message contents (body text, attachments etc). After that the DATA command has been sent to the server from the client, the server will respond with a 354 reply code. After that, the message contenHts can be transferred to the server. When all message contents have been sent, a single dot (“.”) must be sent in a line by itself. If the message is accepted for delivery, the SMTP server will response with a 250 reply code.

7. What port number does SMTP use? For Send Mail Transfer protocol default port number as is 25.

8. What protocols are used to pickup mail?
IMAP and POP

9. What is the purpose of mailertable file?

The mailertable file seems to be used to send emails or similar data packets between machines running Fedora