DNS Record Checker

Overview

• Validates whether the value of a DNS record (A, AAAA, CNAME, MX, NS, TXT, SRV) is correctly formatted, and generates it as a zone file (BIND format) record line.
• Checks IPv4/IPv6 address format, hostname format, and MX/SRV priority, weight, and port numbers, according to the record type.
• Intended for self-checking a DNS record's format before registering it, since format mistakes are easy to miss.

Usage

1. Select A, AAAA, CNAME, MX, NS, TXT, or SRV as the "Record type".
2. Enter the "Name (hostname)" and the value appropriate for the record type (an IP address, hostname, or text). For MX and SRV, also enter values such as priority.
3. Click the "Generate" button to display the record line in zone file format. If the format is invalid, an error is displayed instead.

Example

Type: MX / Name: example.com / Value: mail.example.com / Priority: 10

example.com. 3600 IN MX 10 mail.example.com.

Use Cases

• Self-checking that a DNS record's value is correctly formatted before registering it in a DNS provider's admin panel
• Preventing mail-related configuration mistakes in advance, such as with SPF (TXT record) or MX records
• Correctly assembling a complex format like an SRV record, which includes priority, weight, and port, in zone file format

FAQ

Notes

• Hostname validation is a simplified check based on common label rules (letters, digits, hyphens, underscores; up to 63 characters per label). It may differ from the constraints of an actual DNS provider.
• TXT record values are automatically wrapped in double quotes, with internal backslashes and double quotes escaped. Splitting values longer than 255 bytes into multiple strings is not supported.