Telenegar Mail Check Tool

The Telenegar Mail Check Tool is a specialized email security diagnostic utility designed to verify SPF, DKIM, and DMARC email authentication records, audit domain security posture, and test whether a domain is a temporary/disposable email provider.

It helps system administrators, email engineers, and security auditors ensure outbound mail deliverability, prevent domain spoofing, and validate mail authentication stack configurations.

Tool Features & Parameters

The Mail Check interface provides customized input controls to test email authentication and domain validity:

Parameter	Description	Options / Examples
Domain Name	The domain name to audit for email authentication records.	e.g., `catc.ac.ir`, `telenegar.ir`
DKIM SELECTOR	The prefix selector used by the domain to publish its public DKIM key in DNS (`selector._domainkey.domain.com`).	Default options: `default`, `google`, `s1`, `mail`, `k1`
PROBE	The remote geographical vantage point or probe location executing the lookup.	`Falkenstein, Germany — Hetzner Online GmbH`, domestic Iran probes, regional cloud nodes
Auto-detect DKIM selector	Automatically checks a dictionary of common DKIM selectors if the primary selector is unknown.	Checkbox (tries all common selectors — uses more credits)
Check if domain is disposable	Cross-references the domain against known databases of disposable, temporary, or burner email providers.	Checkbox (against known disposable email domains)

How to Perform a Mail Check

# **Enter Domain Name:** Type the domain into the target input field (e.g., ''catc.ac.ir'').
# **Specify DKIM Selector:** Select or enter a known DKIM selector from the **DKIM SELECTOR** dropdown menu (e.g., ''default'').
# **Auto-Detect Selector (Optional):** If you do not know the domain's active DKIM selector, check the **Auto-detect DKIM selector** box to scan popular selectors automatically.
# **Select Probe Location:** Choose a remote vantage point from the **PROBE** dropdown menu (e.g., ''Falkenstein, Germany — Hetzner Online GmbH'') to test DNS resolution from a specific region.
# **Check Disposable Status (Optional):** Check **Check if domain is disposable** to verify if the domain belongs to a temporary or disposable email service.
# **Execute Audit:** Click the blue **Check** button to run the verification suite and inspect the results.

Key Use Cases & Diagnostics

1. Email Authentication Stack Audit

Verify that the core email security protocols are properly published in DNS to prevent spoofing and improve inbox placement:

SPF Verification: Parses `v=spf1` TXT records, checks authorized IP mechanisms, and detects lookup limit errors (10-lookup max limit).
DKIM Verification: Fetches the public key record at `[selector]._domainkey.[domain]` and validates record format and key strength.
DMARC Policy Audit: Inspects `_dmarc.[domain]` TXT records to confirm policy enforcement (`p=none`, `p=quarantine`, or `p=reject`) and reporting addresses (`rua`/`ruf`).

2. Anti-Spoofing & Phishing Defense Check

Ensure that strict DMARC policies (`p=quarantine` or `p=reject`) alongside SPF and DKIM alignment are configured to prevent bad actors from forging emails using your domain.

*For detailed anti-spoofing strategies, see Email Spoofing and Phishing.*

3. Disposable Domain Screening

Detect whether incoming user registrations or form submissions utilize temporary, disposable email services (e.g., 10-Minute Mail, Guerrilla Mail) to prevent fraud and maintain clean user databases.

4. Email Deliverability Troubleshooting

Pinpoint missing or malformed DNS authentication records when outbound emails are rejected by Gmail, Outlook, or Yahoo with SMTP 550 / 5.7.1 Bounce Errors.

Telenegar Knowledge Base

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