Best SMTP Testing Tools

The SMTP test tool is one type of tool that checks your SMTP server’s health status. First, it connects to the SMTP server, then it sends an email.As we all know, for doing B2B business, email is the third most essential thing for conveying any information.

The majority is not much concerned about mail, and many emails go to spam that that the customer does not check.Before you do the SMTP test, you might be wondering what SMTP is and how it works. This is a simple mail transfer protocol.

It has a set of commands that authenticate and transfer the content directly to the email. It is mainly linked to IMAP or POP3. The main work is to send an email, where IAMP and POP3 help to receive emails. You can say that SMTP is a protocol that allows sending email to people.

Sending an email is important for every business so we should rely on an SMTP server. SMTP test tools only help you to solve SMTP server issues and keep your mail safe. The tool sends a message to the SMTP server, and it solves your problem.Tools quickly check the issue and understand the log details.

It also checks whether it is your login credential or any external threat. By using this tool, only you will be knowing correctly whether emails are reaching the right destination or not.

It provides you with the correct result with less cost and time. Modern SMTP comes with many different integration options where you can leverage those already used tools.

The Result varies depending on the tools but a few results have to be common like IPv6 support, ICAP support, and SOCKS support. Here you will find out some best SMTP tools that are good to diagnose and maintain security properly.

Table of Contents

What is SMTP test tool?
How can I check SMTP server?
Best SMTP Test Tools Features
Best SMTP Test Tools
2. SocketLabs
3. MxToolbox
4. Wormly
5. CheckTLS
6. SSL-Tools
7. ImmuniWeb
8. DNSQueries
9. NetScanTools
10. SMTPDiag Tool
11. Microsoft Analyzer
Also Read

What is the SMTP test tool?

This test will use SMTP to connect to a mail server, run a simple Open Relay Test, and check whether the server has a reverse DNS (PTR) record.

It will also show how long it takes for the mail service to answer. Do an MX Lookup first if you don’t know the address of your mail server.

How can I check SMTP server?

Most mail clients have an account or settings page where you can find the SMTP server address.

The mail transfer agent and SMTP work together to get your email to the right computer and folder across networks. This is done through a process called “store and forward.”

Best SMTP Test Tools Features

Best SMTP Test ToolsFeatures
1. Mailtrap1. Email Testing Environment
2. Inbox Management
3. Collaborative Testing
4. Email Preview
5. Adding support for major email clients
2. SocketLabs1. Email Delivery
2. Email APIs and SMTP
3. Email Parsing and Inbound Processing
4. Email Reporting and Analytics
5.Bounce and handle complaints.
3. MxToolbox1. Email Blacklist Check
2. Email Deliverability Monitoring
3. SPF, DKIM, and DMARC Verification
4. Email Header Analysis
5.Look at the MX score.
4. Wormly1. Server Monitoring
2. Website Monitoring
3. Synthetic Transactions
4. Load Testing
5. Looking at network delays
5. SMTPDiag Tool1. SMTPDiag Tool
2. Authentication Testing
3. Mail Flow Testing
4. DNS Resolution Testing
5. How to read error codes
6. SSL-Tools1. SSL/TLS Scanner
2. SSL/TLS Version and Cipher Suite Analysis
3. Certificate Verification
4. Heartbleed Vulnerability Scanner
5.Find out about DNS and WHOIS
7. ImmuniWeb1. ImmuniWeb
2. Continuous Security Monitoring
3. API Security Testing
4. Web Application Firewall (WAF) Testing
5.Find the attack surface.
8. DNSQueries1. DNS Lookup
2. Reverse DNS Lookup
3. DNS Propagation Check
4. DNSSEC Validation
5.Checker for DNS spread.
9. NetScanTools1. Ping and Traceroute
2. Port Scanner
3. DNS Tools
4. IP Address and Subnet Calculator
5. Useful tools like ping and traceroute
10. CheckTLS1. TLS Encryption Testing
2. STARTTLS Testing
3. Certificate Validation
4. Email Relay Testing
5.Check the DNS and MX records.
11. Microsoft Analyzer1. Checking for security
2. Check the health of Active Directory.
3. A look at how well Windows Server works
4. Watching the Exchange Server
5. Improvements to SQL Server

Best SMTP Test Tools in 2024

2. SocketLabs
3. MxToolbox
4. Wormly
5. CheckTLS
6. SSL-Tools
7. ImmuniWeb
8. DNSQueries
9. NetScanTools
10. SMTPDiag Tool
11. Microsoft Analyzer

1. Mailtrap


You can use Mailtrap to do all three of these things (test, send, and control) with ease.

Using Mailtrap’s Email API or SMTP Relay, you can easily authenticate your SMTP server, send test emails, and then launch your campaign in production.And you get useful alerts and statistics for keeping an eye on key performance indicators.


  • With Mailtrap, you can make fake email accounts and send emails to them.
  • You can send emails to the inbox by connecting your app or email program to Mailtrap’s SMTP and API endpoints.
  • With Mailtrap, you can see a sample of emails that are coming in.
  • The body, topic, and any attachments of the email are all shown.
  • Mailtrap shows you how your email is structured and what it contains.
What is Good ?What Could Be Better ?
Testing EnvironmentLimited Functionality
Email Capture and AnalysisDependency on Internet Connectivity
Email Deliverability Testing
Collaborative Testing

Mailtrap – Trial / Demo

2. SocketLabs


It is one of the best free SMTP test tools used for monitoring, diagnostics, etc. This is very easy and free to download, which also helps troubleshoot SMTP connections.

  • It supports SSL and SMTP server connections, and it also contains a few commands like DATA, RCPT TO, EHLO, and much more.
  • Usually, the SMTP tool is very light, and for download, this user must have Windows and NET 2.0 frameworks.


  • SocketLabs provides a dependable email delivery infrastructure that ensures your emails reach their intended recipients’ inboxes.
  • SocketLabs’ inbound parsing capability allows you to parse incoming emails and extract important data.
  • It provides SMTP relay services for sending transactional and marketing emails from applications or email servers.
  • This provides RESTful APIs and SDKs in multiple programming languages to integrate email sending and management into your apps.
What is Good ?What Could Be Better ?
Reliable Email DeliveryLimited Marketing Automation
Email Analytics and TrackingSupport Availability
API Integration and Developer-Friendly
Template Management

SocketLabs – Trial /Demo

3. MxToolbox


Through this, sending mail is very easy because you just need to enter your mail address and click on the next button.This test will get connected with mail servers that will work through SMTP, and it also has to perform an open relay test so that you can verify with a few servers that include DNS or PTR records.

Not only this, but you can also calculate the response time associated with the mail server. If you do not know your mail server address, you need to review MX Lookup.


  • MxToolbox checks your domain’s DNS settings, IP reputation, SPF and DKIM records, and more to determine email delivery.
  • It examines the most important email blacklists for your IP addresses or websites.
  • MxToolbox includes SMTP diagnostic tools to examine SMTP connections and fix email delivery difficulties.
  • DNS control features in MxToolbox help you maintain your domain’s DNS records.
What is Good ?What Could Be Better ?
Email Delivery MonitoringLimitations of Free Version
Blacklist MonitoringIntegration with Email Service Providers
DNS and MX Record Analysis
Email Routing Analysis

MxToolbox – Trial / Demo

4. Wormly


You may begin the SMTP test in Wormly by entering the IP address or entire domain name of the SMTP server.To complete the verification process, your tool will need your email address to send a request to the SMTP server.

The TCP port used to establish a connection to the SMTP server can be changed from its default value.An SMTP test message can be sent to that address.You can even deny that option if you wish to undertake an SMTP handshake testing.


  • Wormly allows you to track the availability and uptime of your websites, servers, and applications.
  • You can check the status of your servers and how well they’re performing with Wormly.
  • With Wormly, you can monitor your websites’ uptime and performance.
  • Your website’s uptime and performance can be tracked with Wormly.
What is Good ?What Could Be Better ?
Website and Server MonitoringLimited Feature Set
Multiple Monitoring LocationsLimited Integrations
Alerting and Notifications
Real-time Reporting and Historical Data

Wormly – Trial / Demo

5. SMTPDiag Tool

SMTPDiag Tool

If you’re having problems sending email from your server, you can use this tool to identify and fix the problem.The log window will immediately notify you of any issues.

If there was a problem with the transmission, you may see the details in this window.The warning will be sent to you in the form of a message.This SMTP Test Tool is highly user-friendly, making it easy to check the information and  IP address correctly and instantly.


  • SMTP diagnostic tools test SMTP server connectivity and availability by connecting and observing if it responds.
  • With these tools, you may test SMTP server email delivery and sending.
  • SMTP diagnostic tools can verify that SMTP server configurations follow business best practices.
  • SMTP server diagnostic tools can identify the reason of delivery issues.
What is Good ?What Could Be Better ?
The command-line interface may be intimidatingRequires administrative privileges
Command-line interfaceLimited graphical user interface
Detailed error messagesWindows-only tool
Supports multiple tests

SMTPDiag ToolTrial / Demo

6. SSL-Tools


You may check your encryption with this service in a very simple method.A simple tool to enter the domain name and check for vulnerabilities.The STSRTTLS capabilities of the receiving mail server will also be determined.

An SSL certificate is also installed.SSL-Tool is the best security solution available, and it provides comprehensive testing for heartbleed vulnerabilities.


  • You may test the stability and speed of your SSL/TLS server with the help of SSL Tools.
  • Certificate analysis and validation are simplified using SSL tools.
  • SSL-Tools includes vulnerability screening tools to discover potential security issues in your SSL/TLS configurations.
  • SSL-Tools ensures that your server is secure and compliant with industry standards by verifying the SSL/TLS protocol versions it supports.
What is Good ?What Could Be Better ?
SSL/TLS Configuration AnalysisDependency on a third-party service
User-friendly interfaExtensive No automation or monitoring
SSL certificate information
Regular updates

SSL-Tools Trial / Demo

7. ImmuniWeb


When it comes to verifying SSL safety, this program is top-notch.In reality, it’s a no-cost program that safeguards 73M documents.

There are a variety of security checks available with this application, including those for email servers, web servers, SSL certificates, PCI DSS, HIPAA, and more.You, as a user, need not do anything; simply input the address of the mail server or website, and the testing will begin.


  • ImmuniWeb delivers automated and manual web application security testing to detect SQL injection and cross-site scripting.
  • Penetration test security problems are handled centrally.
  • ImmuniWeb can also detect API vulnerabilities, insufficient encryption, and other security issues.
  • The platform supports GDPR and PCI DSS compliance.
What is Good ?What Could Be Better ?
Comprehensive security testingDependency on the platform’s availability
Advanced testing techniquesReliance on a third-party service
Expert analysis and reporting
Compliance support

ImmuniWebTrial / Demo

8. DNS queries

DNS queries

This is a very useful utility for ensuring the server is healthy and operational.At first, it tries to establish a connection with the mail server and transmit the message, increasing the likelihood that it will be delivered.

The outcome is presented in a web page format.You need only enter the hostname for the test to begin using this highly effective and professional tool.


  • DNS monitoring tools evaluate DNS queries and responses to ensure DNS infrastructure availability and proper operation.
  • Its security features protect the DNS infrastructure from DNS spoofing, cache poisoning, and DDoS attacks.
  • This analytics solutions provide DNS query trends, traffic volumes, response times, and more.
  • DNS load balancing distributes DNS queries across several servers or IP addresses to improve performance, availability, and fault tolerance.
What is Good ?What Could Be Better ?
Efficient name resolutionSingle point of failure
Caching for improved performanceSecurity risks
Load balancing and fault tolerance
Reducing network congestion

DNS queriesTrial / Demo

9. NetScanTools


It’s made to work with SMTP mail servers, so sending emails is a breeze.The header parameters are always accessible.This allows for SMTP authentication, which requires the user to enter a password in addition to their username before sending mail over the server.

This utility will email the attachment to you.You may open up those folders to see how SMTP and NetScanTools Pro are talking to one another.In addition, it runs over fifteen regular relay tests that communicate with the SMTP server.

You can see which one is the best and decide which test report you wish to perform in your web browser.This is also the most efficient method of transferring data between NetScanTools Pro and an SMTP server.


  • Network addresses, broadcast addresses, subnet masks, and CIDR notation are NetScanTools’ capabilities.
  • Network scanning tools in the suite find and map network elements.
  • The suite includes IP, MAC, and port scanners for finding and mapping network entities.
  • The suite uses ICMP ping and traceroute to determine if a source or target is reachable and the optimum network path.
What Could Be Better ?
Comprehensive toolsetReliance on local installation
User-friendly interfaceAdvanced features require expertise
Network troubleshooting capabilities
Security analysis features

NetScanToolsTrial / Demo

10. CheckTLS


You can verify the integrity of your email’s encryption with CheckTLS.It includes an EmailSentry outlook, which makes sure that you have sent emails, and this is absolutely private, safe, and legal.

HIPAA, PCI, GDPR, CCPA, and other regulations all give their stamp of approval.Primarily, it serves to keep your email safe.CheckTLS performs tests on your email and assists in fixing any problems it finds.


  • You may verify your email server’s integrity and safety with the help of CheckTLS.
  • You can use CheckTLS to ensure that your email server is set up and secured properly.
  • CheckTLS examines your email server’s SSL/TLS certificates.
  • CheckTLS verifies the availability of supported encryption algorithms and cipher suites on your mail server.
What is Good ?What Could Be Better ?
Email Security TestingLimited Automation and Scalability
Compliance VerificationDependency on Email Systems
Detailed Test Reports
Easy-to-Use Interface

CheckTLSTrial / demo

11. Microsoft Analyzer

Microsoft Analyzer

It enables remote connectivity, which necessitates extensive testing to yield results. The incoming and outgoing SMTP email traffic is monitored.Email servers conduct a variety of tests when sending the domain in SMTP email, and this log displays the results as they come in.

To perform tasks such as RBL checks, reverse DNS lookups, and sender ID validation on the outbound end, SMTP makes use of IP addresses.

Microsoft AnalyzerTrial /Demo


Sending an email is only the first step in connecting with your client. It is always better to find out whether every email is reaching or not at the correct destination.

These SMTP Test Tools are used to fix potential risks, and they make sure that emails do not reach the receiver’s spam box. This tool also safeguards email security and increases durability.

Also Read

Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.