Migrate Legacy Linux Platform

I’m planning a full move of a 29-year-old custom hosting platform over to a fresh VPS reseller account and I need a seasoned Linux infrastructure engineer to handle every step of the transition. The current stack spans CentOS 6 and 7 with Apache web services, Sendmail + Dovecot mail delivery, BIND-named for DNS, Mailman mailing lists, DKIM/SPF records, MX routing, virtusertable aliases, and a range of hand-tuned legacy scripts that keep it all working together.

The web, mail, and DNS layers (Apache, Sendmail, Dovecot) all carry bespoke configuration tweaks that must be kept intact. I have detailed documentation for these customisations, including conf file excerpts, directory layouts, and notes on historical work-arounds, so you will not be reverse-engineering them from scratch. Your mission is to recreate the environment on the new VPS reseller platform, validate service parity, and cut the final switchover with minimal downtime.

Key expectations
• Clean migration of Apache vhosts, SSL certificates, and log rotation rules
• Accurate port of Sendmail/Dovecot mailflow, user mailboxes, filters, virtusertable, DKIM & SPF records
• Replication of BIND zones and MX priorities, with registrar or glue record updates as needed
• Mailman list export/import and testing of list delivery
• Post-migration validation: HTTP(S) responses, SMTP/IMAP connectivity, DNS propagation, and bounce/relay checks
• Clear rollback plan in case of unforeseen issues

I will provide root access to both old and new servers, the documentation set, and test accounts for verification. If you have deep experience moving non-cPanel, non-Plesk infrastructures—especially those built around Sendmail—and you’re comfortable scripting or automating repeatable steps, I’d like to hear how you would approach the job and how soon you can begin.