Documentation

Introduction DNS Architecture Installing BIND9 named.conf Deep Reference Zone File Anatomy All DNS Record Types Primary Secondary Replication Multi Domain DNS Servers Split Horizon DNS Internal Mail Routing Resolver Internals Linux Resolver Internals FreeBSD DNSSEC Full Guide TSIG Keys Zone Transfers AXFR IXFR Dynamic DNS Updates Caching Behavior Performance Tuning Hidden Primary Architecture Large Scale DNS Design Troubleshooting DNS

Internal Mail Resolution

Internal Mail Resolution

Internal DNS can return private IPs while public DNS returns external IPs.

mail.example.com IN A 10.0.0.20