Email Validation - Settings

Validation Settings

The settings page lets you control how the email validator behaves. Changes apply to both single and bulk validation.

Accessing Settings

1. Go to Email Validator from the sidebar.
2. Click the Settings tab at the top of the validator page.

Validation Level

Choose between two levels:

• Basic (Fast) — Format check, MX records, disposable/spamtrap detection, typo suggestions. Fast and does not require port 25 access.
• Advanced (SMTP + DNS) — Everything in Basic plus SMTP mailbox verification, SPF, DMARC, DNSBL blacklist checks, and reverse DNS. More accurate but slower and requires port 25 or an external SMTP server configured below.

Performance (Threads)

Controls how many emails are validated in parallel during bulk validation.

• Range: 1 to 50 threads
• Recommended: 4-10 threads for most use cases
• Higher thread count = faster validation but uses more bandwidth and may trigger rate limits on some mail servers
• If you see many timeout errors, try lowering the thread count

External SMTP Relay (No Auth)

If port 25 is blocked on your network (common on home/office internet), you can route SMTP verification through an external relay server. The relay forwards verification requests to the destination mail server on your behalf.

1. Check Enable external SMTP relay.
2. Enter the relay Host (e.g. smtp.relay.example.com).
3. Enter the relay Port (usually 25).
4. Click Save.

This option does not require authentication. You need access to an open relay or a relay server you control.

External SMTP Server (Authenticated)

Alternatively, you can use your own SMTP server with authentication for verification. This is useful if you have a PowerMTA server or any SMTP server you can authenticate against.

1. Check Enable authenticated SMTP server.
2. Enter the server Host (IP address or hostname).
3. Enter the Port (25, 465, or 587).
4. Enter your SMTP Username and Password.
5. Click Save.

Note: The relay and authenticated SMTP options are mutually exclusive. Enabling one disables the other. If neither is enabled, the validator connects directly to destination mail servers on port 25.

Port 25 Notice

Advanced validation requires connecting to mail servers on port 25. Many ISPs and cloud providers block outbound port 25 on residential and some business connections. If you cannot use Advanced validation directly, configure one of the external SMTP options above.

Settings Persistence

All settings are saved automatically to your local machine and persist between sessions. You do not need to reconfigure them every time you open PMTAcore.