Sendmail Version 8x MTA

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
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• 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
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• 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
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• 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)
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• 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
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• 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
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• 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
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• 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
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• 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
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• 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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• Sendmail - Smart Host Configuration
  • Discuss Smart Host applications
  • Configure Sendmail to use remote server as a Smart Host
  • Rebuild configuration files
  • Test local mail routing
  • Test smart host routing
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• Sendmail - Null Client Configuration
  • Discuss Null Client applications
  • Undefine Smart Host configuration
  • Configure Sendmail as a null client
  • Test mail routing as a null client
  • Confirm forced SMTP route
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• Sendmail - Virtual Domains
  • Explain applications
  • Define basic-global virtual domains applied to all mailboxes
  • Update DNS configuration to route messages to appropriate Virtual Domain server
  • Confirm delivery of messages to users at virtual domain
  • Add new DNS zone for additional domain to route traffic accordingly
  • Discuss virtual user tables applications
  • Updated Sendmail.cf to include virtual user tables support
  • Define virtual user domains hash
  • Define virtual user maps
  • Test delivery to various users at various domains
  • Define and test a catchall address for a virtual domain
  • Rebuild virtual user maps using makemap
  • Relay virtual domains to remote recipients
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• Sendmail - Malware Framework
  • Discuss Malware Framework (MailScanner/ClamAV/SpamAssAssin)
  • Dowload MailScanner
  • Download Clam Anti-Virus (ClamAV)
  • Download SpamAssAssin
  •  
  • Clam Anti-Virus (ClamAV)
    • Install requisite ClamAV components
    • Compile & install ClamAV
    • Identify key ClamAV binaries
    • Update ClamAV configuration files for basic operation
    • Update ClamAV definitions
    • Invoke ClamAV as a daemon
  •  
  • SpamAssAssin Installation
    • Identify requisite SpamAssAssin components
    • Compile & install SpamAssAssin
    • Invoke SpamAssAssin as a daemon
  •  
  • MailScanner Implementation
    • Compile & install MailScanner
    • Identify MailScanner-related directories
    • Explore MailScanner's primary configuration
    • Enable ClamAV & SpamAssAssin support
    • Alter Sendmail queue configuration to support MailScanner
    • Restart Sendmail
    • Start MailScanner
    • Test message delivery through malware framework
    • Test sample Spam through malware framework
    • Test sample Virus-laden file through malware framework
  •  
• Sendmail - Transport Layer Security (TLS) Configuration
  • Discuss features & benefits
  • Discuss clear-text implications & caveats
  • Generate mail as a TLS client
  • Confirm one-way encryption
  • Generate PKI usage keys
  • Configure & confirm TLS Server support
  • Generate message responses
  • Confirm bi-directional encryption
  • Evaluate results
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Sums

• Various Tools
• Remote Confirmations
• File Metadata
• File Fragments
• Compress Content
• Archive Content
• DIR Hierarchy
• Password Sums
• Shared Secret
• Restrict History
• Downloaded Content
• Encrypt Content
• Site Credentials
• Site COOKIE
• Site COOKIE - Unique

CentOS9x Stream Administration

• Initial Environment
• ls, pwd, cd, cp, mv, rm, mkdir, rmdir, whoami
• alias, cat, file, chmod, chown, history
• STD(IN|OUT), Pipes, Redirection, Command Chaining
• ps, df, top, free
• Pagers, W-Commands
• Checksums
• Awk | Sed | Grep Usage
• BASH SHELL Environment
• Compression | Archival Tools
• SSH Equivalence
• SHELL Quoting
• Propagate Environment
• Secure Clients

• Identify Standard File Types
• Standard File Permissions
• Symbolic Links
• Transfer Permissions

• Identify SWAP environment
• Provision dedicated SWAP partitions
• Add | Remove SWAP from pool as needed
• Provision File System-based SWAP
• SWAP Share
• SWAP Persistence
• Identify default storage configuration
• Provision new storage as needed
• XFS - File System
• XFS - Grow File System
• Identify LVM defaults
• Add new partitions to LVM management
• Allocate storage to LVM Volume Groups
• Create Logical Volumes (LVs) as needed
• Overlay File System and mount where applicables
• LVM - Resize
• LVM - Mixed FS
• LVM - SWAP

• Features
• Install
• Defaults
• General Usage
• Update Accounts

• Defaults
• Shared PASS Gen
• Unique PASS Gen
• Encrypted PASS Gen
• Update Accounts
• Groups

• Discuss features | limitations
• Identify default system-wide schedule
• Peruse various default Cron Jobs
• Schedule simple job and monitor recurrence
• Evaluate results

• Peruse Default CONF
• Discuss Syslog Rules
• Explore Log Rotate defaults
• Ensure rotated logs are compressed
• Extend default retention scheme
• Force Log Rotation as needed

• Explore Default environment
• Install PKGs
• Dump important metadata from packages
• Apply Updates

• Default CONF
• Add | Confirm IPs as needed

• Install
• Copy Configuration
• SELinux - Confirm
• TLS | SSL Services
• cURL Client Tests
• Virtual Hosts
• ENC Sites Only

• SFTP Only USER
• SFTP Only USER - NOLOGIN
• SFTP Only Group - Control
• NMap Intro

SysLOG with rSysLogD

• Discuss Features
• Default Environment
• Kernel Firewall LOG
• Split LOGs by Priorities
• UDP | TCP Logging
• Dual L4 Logging
• Multiple Hosts
• Basic Queueing
• Reliable Event Logging Protocol (RELP)
• RELP - Remote Only
• RELP Only
• Traditional to RELP
• SysLOG Clear-Text - Confirm
• Property Filters
• Expression Filters
• Relay Chain

Netfilter Tables

• Features
• SSHGuard
• Ruleset Basics
• Persistence
• Sample Rules
• Inbound Filtering
• Dormant Table
• Manage Tables | Chains | Rules
• Counters
• Sets
• LOG Basics
• LOG with Sets
• Closed-Port LOGs
• LOG Options
• Re-Route LOGs
• Jump Targets
• Chain Jumping
• GoTo Chains
• Meta Selectors

Debian 12x Administration

• Features
• Download
• Graphical Install
• Text Install
• Post-Install Tweaks

• Explore usage of the following useful commands
• tty | /dev/pts | w | whoami | who
• set | env | export | unset
• cat | echo | touch | rm
• pwd | ls | cd | mkdir | alias | umask
• head | tail
• dd
• find
• history
• STDIN, STDOUT, STDERR, UNIX Pipes, Redirection, Command Chaining
• ps, df, free, top, dd
• stat, which, w, who
• tar | gzip | bzip2 | xz
• ZSH Setup

• Network Tools | IP Configuration
• Examine default IP configuration
• Extend IP configuration to facilitate additional addresses
• Static IP Config
• Dual: Dynamic | Static Config
• Multiple Interfaces
• Dual Network Services
• Confirm communications

PHP One-Liners

• General Usage
• Count Lines
• Word Count
• Count Chars
• Split Lines into ARRAY
• Count Instances of Fields
• Transform Delimiters
• Anonymize LOGs
• Extract Unique SRCs
• Lines by Error Code
• LOG By Code
• Summarize Error Codes
• Pre-Seed Error Codes
• Random Strings
• Varied Passwords
• Expose Undefined Passwords
• Outdated Passwords
• Hash | Un-Hash

Cloud Storage with GlusterFS

• Discuss Features:
• Default Volume Type
• Common Volume Types
• Transport Types
• File System Support
• Storage Model

• Features
• Provision Storage
• Allocate GlusterFS Brick
• Persistence
• Generate IO
• Multiple File Systems
• Various Sizes
• Stop | Remove Volume
• Reconstitute Volume
• Server Mount
• Evaluate

OpenPGP with GPG

• Discuss Features:
• Primary Tool
• Private | Public Keys
• Public Key Cryptography Standards (PKCS)
• Encryption | Decryption
• Signing | Verification

• Features
• General Usage
• Create Content
• Encrypt
• PassPhrase Protect
• Binary | Text Encryption
• Share
• Decrypt

SSL-TLS with OpenSSL

• Discuss Features:
• Primary Tool
• Private | Public Keys
• Certificate Signing Requests (CSRs)
• Self-Signed Certificates
• Public Key Cryptography Standards (PKCS)
• Encryption | Decryption
• Random String Generation
• Message Digests
• SSL-TLS Client

• Features
• General Usage
• Retrieve Site Certificates
• Determine OCSP Configuration
• Probe supported TLS Versions
• Extract Certificate for local usage
• Retrieve Certificate with NMap
• Retrieve Certificate Chain

• Discuss
• Generate Private Keys
• Generate Correlating CSRs
• Confirm Keys | CSRs
• Self-Signed Certificates

SSH Variables

• Discuss Features
• Bare VARs
• SSH Client
• Double Quotes
• Single Quotes
• SSH Environment

SHELL Variables

• Discuss Features
• Terminal (TTY)
• CLI Arguments
• Process ID
• Backgrounded
• SHELL Local
• Environment
• Persistence
• Aliases
• Command Substitution
• Increment | Decrement
• Dynamism