A DNS zone is the portion of DNS namespace managed by specific nameservers.
What's in a Zone
Each zone contains:
- One or more domains
- DNS records for those domains
- Configuration for how records are served
Zone File Structure
Basic zone file:
$TTL 86400
@ IN SOA ns1.example.com. admin.example.com. (
2024010101 ; Serial
3600 ; Refresh
1800 ; Retry
604800 ; Expire
86400 ) ; Minimum TTL
; Nameservers
@ IN NS ns1.example.com.
@ IN NS ns2.example.com.
; Records
@ IN A 192.0.2.1
www IN A 192.0.2.1
@ IN MX 10 mail.example.com.
Record Types in Zones
- SOA: Start of Authority (required, one per zone)
- NS: Nameserver records
- A/AAAA: IP addresses
- CNAME: Aliases
- MX: Mail servers
- TXT: Text data (SPF, DKIM, etc.)
Managing Zones in ArkHost
- Go to Domains → DNS Manager
- Click pencil icon to edit zone
- Add/modify/delete records as needed
Serial Numbers
Format: YYYYMMDDNN
- 2024010101 = January 1, 2024, revision 01
- Increment when making changes
- Secondary servers check this to know when to update
Reverse DNS Zones
Maps IP to hostname (PTR records). Usually managed by:
- Your ISP for home/office IPs
- Your hosting provider for server IPs
Example PTR record:
1.2.0.192.in-addr.arpa. IN PTR mail.example.com.
Common Issues
- Zone not loading: Check SOA syntax
- Records not updating: Increment serial number
- SERVFAIL errors: Missing required records (SOA, NS)
