You can use OpenSSL. If you have to check the certificate with STARTTLS
, then just do
openssl s_client -connect mail.example.com:25 -starttls smtp
or for a standard secure smtp port:
openssl s_client -connect mail.example.com:465
Related Posts:
- Authentication versus Authorization
- When you use ‘badidea’ or ‘thisisunsafe’ to bypass a Chrome certificate/HSTS error, does it only apply for the current site? [closed]
- When you use ‘badidea’ or ‘thisisunsafe’ to bypass a Chrome certificate/HSTS error, does it only apply for the current site? [closed]
- Convert a CERT/PEM certificate to a PFX certificate
- When you use ‘badidea’ or ‘thisisunsafe’ to bypass a Chrome certificate/HSTS error, does it only apply for the current site?
- Convert .pfx to .cer
- how fix “this certificate cannot be verified up to a trusted certification authority”
- What is a Pem file and how does it differ from other OpenSSL Generated Key File Formats?
- How do I deal with a compromised server?
- 100% uptime for a web application
- How to assign permissions to ApplicationPoolIdentity account
- Any benefit or detriment from removing a pagefile on an 8 GB RAM machine?
- How do I view the details of a digital certificate .cer file?
- Windows Server restart / shutdown history
- Dealing with HTTP w00tw00t attacks
- How Often Do Windows Servers Need to be Restarted?
- ‘git’ is not recognized as an internal or external command
- How to write trycatch in R
- how to use proxy on youtube-dl?
- What’s the best approach for generating a new API key?
- How to do vlookup and fill down (like in Excel) in R?
- Using “super” in C++
- What is the difference between application server and web server?
- Code-first vs Model/Database-first
- How to resolve git’s “not something we can merge” error
- How can I delete all of my Git stashes at once?
- How to create temp table using Create statement in SQL Server?
- Error while trying to retrieve text for error ORA-01019
- What is meant by diameter of a network?
- How can I center
- into a div?
- Popup window in PHP?
- LaTeX table too wide. How to make it fit?
- R: NaNs produced
- How does the SQL injection from the “Bobby Tables” XKCD comic work?
- How to calculate Internet checksum?
- WordPress broken app to try wpscan kali tool
- wordpress login wp-login.php change url
- How to Protect Uploads, if User is not Logged In?
- Can I rename the wp-admin folder?
- What are the pros and cons of using a custom front-end to retrieve content from a WordPress back-end
- Disable external access to REST API Endpoint
- WordPress salts set in config and database
- What is the difference between strip_tags and wp_filter_nohtml_kses?
- How to secure WordPress XMLRPC?
- Questions about brute force attacks on the admin username, coming from amazon IP addresses
- How do I bypass WordPress 404 handling?
- wp-config.php modified?
- Woocommerce reviews xss issue [closed]
- Upgraded to latest version – 3.0.3 and Now I get a “sufficient permissions to access this page” error
- Is wp_kses the right approach in sanitizing this string?
- Reset Password policy
- Renaming install.php for security?
- making media URL secured
- Use global variables or function that returns said variables for site-wide private-ish WP settings?
- Use Google authentication for pages within a website [closed]
- Vulnerability Concern From the Plugin or From Not Updating the Plugin?
- Is a very simple theme secure enough?
- Import local site to WordPress.com
- Can I make the post type value dynamic in ajax.php in wordpress
- Posts feed number of posts
- How can I debug what is wrong ? Featured images stopped showing
- How do I determine if the user who registered is not spam?
- Secret keys in SCM
- Asking help regarding potential malware
- $.ajax results in 403 forbidden
- Scan multiple websites for malware that are in same webhost root?
- Bootstrap theme embedded iframes are distorted [closed]
- Is there default meta boxes types that handles types and sanitization?
- Ajax Security regarding user priviliges and nonces
- PHP Code Sniffer – WordPress VIP Coding Standards
- WP upload/select image , isn’t this a security issue?
- Load all files from folder in theme – Security concerns?
- Are image addresses security relevant?
- Directory to store secure file
- How can I give someone server access to only duplicate and modify a site?
- How to set environment variable in systemd service?
- Symlink not updating as expected when using an absolute with relative path
- How to include multiple domains in an spf TXT Record
- Is it normal to get hundreds of break-in attempts per day?
- Physically locating the server
- Good tools that fit on a thumb drive [closed]
- How do you answer yes for yum install automatically
- How to handle security updates within Docker containers?
- All servers flooded by salt water, is it possible to recover data from multi-platter drives?
- How can I implement ansible with per-host passwords, securely?
- REJECT vs DROP when using iptables
- How to check if I’m in screen session?
- How to zip/unzip files in Powershell?
- Cooling Server Closet – No A/C Is Possible
- Is it better practice to buy RAID disks individually vs. in bulk?
- What range of MAC addresses can I safely use for my virtual machines?
- What sysadmin things should every programmer know?
- Why do systems generally disable virtualization by default in BIOS settings?
- 10 servers to administer and I’m a history major [closed]
- Making `wget` not save the page
- How can I find the path to an executable in OSX
- How to accurately check if package is installed in yum?
- What is the difference between SAN, NAS and DAS?
- Do you skip a rack unit between servers?
- How to find source of these strange SQL queries?