sudo rpm -Uvh https://repo.hmc.com/hmc-release-22-1.noarch.rpm sudo add-apt-repository ppa:hmc/22 sudo apt update sudo apt install hmc-mail-checker22 After installation, the binary is available as hmc-mail-checker22 . You can verify the version with:
sudo ln -s /opt/hmc/bin/hmc-mail-checker22 /usr/local/bin/hmc-mail-checker22 Integrating with Nagios / Zabbix You can use HMC Mail Checker 22 as a monitoring plugin. For example, in Nagios: hmc mail checker 22
hmc-mail-checker22 --test-alias postmaster --expected-forward admin@contoso.com Add this to root's crontab to run a check every 6 hours and email the administrator: sudo rpm -Uvh https://repo
| Feature | Description | | :--- | :--- | | | Lists messages stuck for > 1 hour in the HMC 22 deferred queue with reason codes. | | SMTP Transaction Replay | Records a real-time .pcap of the SMTP conversation for TLS debugging. | | DKIM Signature Verifier | Compares the signature header against public keys stored in HMC 22's DNS cache. | | Local Delivery Test | Writes a test message to a user's Maildir and checks for courierimap flags. | | Greylisting Predictor | Simulates three connection attempts to see if HMC's greylisting delays delivery. | Installation Guide (CentOS / AlmaLinux / Ubuntu) HMC Mail Checker 22 is typically distributed via the official HMC repository. Here is the standard installation method: For RHEL-based systems (CentOS 7/8, AlmaLinux 8/9): sudo yum install epel-release -y sudo yum install hmc-mail-checker22 -y If the package is not found, add the HMC repo: | | SMTP Transaction Replay | Records a real-time
The --monitor-mode flag prints "OK" or "CRITICAL" and exits with the appropriate Nagios code. To verify that HMC 22 processes /etc/aliases correctly:
define command command_name check_hmc_mail command_line /usr/local/bin/hmc-mail-checker22 --domain $ARG1$ --to $ARG2$ --monitor-mode