Mail Server Tools
Test your SMTP connection, send a test email, verify SPF/DMARC records, and check whether your IP is blacklisted.
- Free, no sign-up
- Credentials are never stored
- Results in seconds
SMTP Connection Test
Enter your mail relay, sending server or your own SMTP credentials. Connection and authentication are tested step by step.
Your credentials are used only for this test request and are not stored.
See exactly where your connection breaks
We talk to your server the way a mail client does and report every step: what the server answered, how long it took, which TLS version and certificate it presented, and what to fix.
Send a Real Test Email
A real test email is sent through the SMTP server you provide.
Left empty, the username is used as the sender address.
Your credentials are used only for this test request and are not stored.
Prove that your mail really arrives
We hand a real message to your SMTP server and tell you what it answered. Then we show you how to read the headers of the received message to confirm SPF, DKIM and DMARC.
Mail Security Analysis
Type your domain; we inspect your MX, SPF, DKIM and DMARC records and score how well you are protected against spoofed email.
DKIM selectors cannot be discovered through DNS. We try the common ones for you; if you know your own selector, enter it here for a definitive result.
Is your domain protected against spoofing?
The analysis takes a few seconds. For every record we show its status, the danger it creates when missing, and the most secure configuration as copy-ready DNS records.
DMARC Policies: none, quarantine and reject
When someone sends a fake email impersonating your domain, what happens under each policy?
p=none (monitor only)
The receiving server takes no action against mail that fails the checks; it delivers the message as usual and only sends you a report.
Zero protection. A forged invoice that appears to come from "accounting@yourdomain.com" lands in your customer's inbox like any genuine message.
Only at the start, for 2-4 weeks: to collect reports, identify every genuine source that sends mail for your domain, and fix what is missing.
p=quarantine (send to spam)
Mail that fails the checks is accepted but placed in the spam (junk) folder instead of the inbox.
The same forged invoice no longer shows in the inbox, but it is still in the mailbox: a user who looks in the spam folder can open it, or even mark it as "not spam".
As the intermediate stage, after you have fixed your genuine sources. If you overlooked a source, its mail is not lost; it can be recovered from the spam folder.
p=reject (refuse)
The receiving server turns away mail that fails the checks during the SMTP connection itself; the message reaches no folder at all.
The forged invoice never reaches the recipient. The remaining risk is on your side: if one of your sending sources (CRM, newsletter service, website form) is not yet covered by SPF or DKIM, its genuine mail is rejected too.
This is the target end state. Move to it once the reports show all of your genuine sources passing the checks; on domains that send no e-mail at all, apply it immediately.
SPF “all” Qualifiers
The all term at the end of your SPF record tells receivers what to do with email from a server that is not on your list.
Blacklist (DNSBL) Check
Enter your mail server IP (or domain); it is queried against known blacklists including Spamhaus.
Is your mail server on a blacklist?
One listing on a major blacklist is enough for Gmail, Outlook and corporate filters to reject your email. We query the lists that matter and tell you what each result means.
What Are Mail Server Tools and What Do They Do?
IzHost Mail Server Tools is a free toolkit that lets system administrators, developers and businesses test the health of their email infrastructure in one place. It tests your SMTP server connection and authentication step by step, verifies delivery by sending a real test email, analyses your domain's SPF/DMARC/MX records, and checks whether your server IP is on known blacklists (Spamhaus, SpamCop, Barracuda and more).
Are your emails landing in spam, failing to send, or are you wondering "why won't my mail go through"? These tools diagnose the most common causes of email deliverability problems — misconfigured SMTP, missing SPF/DMARC records, blacklisted IP addresses — in seconds. No installation required; everything runs from your browser.
Tools and Use Cases
SMTP Connection & Authentication Test
Enter your server, port (25/465/587), username, password and encryption (Plain, STARTTLS or SSL/TLS); we test each step — connection, EHLO, STARTTLS and AUTH — separately. Instantly see whether your mail relay, sending server or your own SMTP account works, and pinpoint wrong credentials or port/encryption mismatches.
Send a Real Test Email
Using the SMTP credentials you provide, we send a real test email to the recipient you choose. Verify end-to-end whether the email reaches its destination, lands in spam, and that your server can actually send mail.
Mail Security Analysis: SPF, DKIM, DMARC & MX
Enter your domain; we analyze your MX, SPF, DKIM and DMARC records and give you a security score out of 100. For every record we show its status, the danger a missing record exposes you to (spoofed email, phishing, landing in spam) and the most secure configuration for your domain as copy-ready DNS records. We also explain, with examples, the difference between the DMARC p=none, quarantine and reject policies and the safe staged rollout.
Blacklist (DNSBL) & Spamhaus Check
Queries your mail server IP or domain against well-known DNS blacklists (DNSBL) including Spamhaus ZEN, SpamCop, Barracuda, Mailspike and UCEPROTECT. If your IP is blacklisted, most providers block your email — this check helps you catch the problem early.