Focus: Sendmail Version 8x MTA 
Duration: 14 Hours

Course Objective
LinuxCBT Sendmail v8 Edition - Module I

Sendmail - Installation
Network & systems architecture review
Download current Sendmail v8.x.x source files
Import PGP-compatbile public keys
Verify source archive against imported public keys
Discuss required applications
Install GNU C Compiler (GCC) and ancillary applications
Backup existing Postfix implementation and prepare for Sendmail installation
Explore Sendmail source tree - identify key components
Configure & compile Sendmail
Discuss M4 & CF configuration files (sendmail.{mc,cf}, submit.{mc,cf})
Discuss default Sendmail operating modes - MSP & MTA
Prepare default Mail Submission Program (MSP) configuration based on MC
Prepare default Mail Transfer Agent (MTA) configuration based on MC
Install Berkeley DB libraries for hashed lookups
Complete installation
Explore post-installation Sendmail environment

Sendmail - Mail Submission Program (MSP) mode
Discuss local injection of messages
Explain required Sendmail MSP shell arguments for queue-runner mode
Start Sendmail in MSP mode
Verify Operating System (OS) results using BASH exit status
Verify monitored queue in MSP mode
Examine resultant Sendmail MSP Process Identification (PID) file creation
Kill running instance of Sendmail in MSP mode
Invoke Sendmail queue-runner mode
Inject test messages into the local queue
Examine the queue files generated by Sendmail MSP
Examine Syslog configuration using GREP
Discuss Sendmail logging
Identify Sendmail log files
Examine specific Sendmail log entries using GREP

Sendmail - Mail Transfer Agent (MTA) mode
Discuss Sendmail's separation of duties; MSP/MTA
Explain required shell arguments for Sendmail MTA mode
Invoke Sendmail in MTA mode running as a daemon
Confirm Sendmail running in MTA mode
Force delivery of locally-injected messages
Confirm delivery of queued messages

Sendmail - Local Mail
Discuss Sendmail's local delivery mechanism
Explore & discuss legacy /var/spool/mail directory
Identify user mbox files
Discuss mbox permissions
Illustrate local mail injection flow
Use mutt MUA to retrieve locally delivered mail
Use mutt to reply to envelope sender by local injection using MSP
Identify local mailer (procmail) used by Sendmail MTA
Invoke Sendmail in verbose mode
Attempt delivery to valid and invalid users & examine output
Explain Sendmail verbose-mode transcript (local vs. remote)

Sendmail - Logs
Discuss Syslog semantics (facilities & levels)
Discuss log rotation
Examine logs & discuss entries
Parse logs for interesting entries
Identify sourced messages
Discuss record types (receipt vs. delivery attempt(s))
Follow the message trail based on queue ID
Explain Sendmail fields
Identify PID related to various delivery attempts
Identify total delivery time and transfer time

Sendmail - Aliases
Discuss aliases applications
Identify aliases database
Explain Sendmail's aliases expansion logic
Discuss the default aliases - (mailer-daemon, postmaster, etc.)
Test delivery to defined aliases
Define additional aliases
Rebuild aliases database using newaliases to route messages accordingly
Verify deliverablility of aliases database entries
Test delivery of messages to newly-defined aliases
Examine Sendmail logs to view transcript of delivery to aliased user
Explain the different types of supported Sendmail aliases
Define lists using aliases - one-to-many mappings
Test delivery to lists
Define alias to deliver messages to mbox-compliant file
Debug I/O errors related to Sendmail's attempt to write to mbox-compliant file
Implement lists using file system includes
Define piped aliases to redirect messages to the input stream of other applications
Implement Sendmail's per-user.forward file for user-based message routing
Setup aliases using pipes to the vacation program to enable auto-response

Sendmail - Simple Mail Transfer Protocol (SMTP) Mail
Discuss SMTP prerequisites
Examine local name resolution configuration
Confirm resolution of remote Sendmail server
Identify available remote recipients
Compose and deliver message to remote recipient
Confirm receipt
Reveal returned message headers using mutt MUA
Disable message forwarding on remote host
Confirm receipt of smtp-based messages
Explain Sendmail's name resolution logic during delivery attempt
Emulate Sendmail's name resolution logic to illustrate logic
Demonstrate Sendmail delivering messages based on static HOSTS resolution
Disable static name resolution for remote host
Debug message delivery errors related to invalid name resolution
Create DNS entry for remote server on primary DNS server
Confirm DNS resolution using system tools
Confirm mail delivery based on DNS resolution

Sendmail - Mail Exchange (MX) based messaging
Explain Sendmail's name resolution logic
Use system tools to determine MX handler
Attempt delivery to undefined MX handler
Update DNS configuration to include MX & A records for second-level domain
Attempt delivery to defined MX handler
Confirm delivery based on MX resolution via logs and MUA
Explain MX distances (priority) field
Define additional MX host for second-level domain in DNS zone
Test delivery to backup MX host for failover

Sendmail - m4 Configuration Technique
Discuss Sendmail.cf
Explain advantages of using m4
Identify m4 templates in Sendmail source tree
Explain m4 templates hierarchy
Describe the structure of standard Sendmail m4-compliant files
Use m4 to generate new Sendmail.cf file
Increase logging verbosity
Reload current instance of Sendmail and examine output
Restrict the number of recipients
Restrict the size of each message
Use m4 to generate and test new configuration features
Sendmail - Masquerading
Discuss masquerading features and applications
Explore default Sendmail masquerading configuration using MUA
Alter Fully Qualified Domain Name (FQDN) of outbound messages using masquerading
Regenerate Sendmail.cf using m4 technique
Configure system to receive messages for new FQDN defined using masquerading
Alter message envelope using masquerading feature
Add Windows 2003 Host to DNS configuration & confirm resolution
Masquerade outbound domain to reflect second-level domain

Sendmail - Relay Control
Discuss Sendmail's default relay rules
Configure promiscuous relay & test consequences
Relay mail to Internet-based host and confirm delivery using SSH
Restrict relaying by defining relay domains
Define & test file-based relay domains to permit hosts & subnets to relay
Recompile Sendmail.mc using m4 technique
Examine relaying with unresolvable domains
Confirm relay to Internet-based host using relay domains and Windows 2003 Host
Discuss benefits of using access db
Define mc directives for access db invocation
Create access db file using makemap
Explore access db directives
Discuss mailertable feature
Define mailertable with forced SMTP routes
Simulate DMZ-based MTA-front-end relaying messages to corporate back-end MTA
Test results
Confirm SMTP Auth pre-requisites
Configure SMTP Auth support
Recompile Sendmail to support SMTP Auth
Test relaying from Outlook Express on Windows 2003 Host

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