An essential skill for email administrators is being able to dive into the command line to troubleshoot email delivery and connectivity problems.  In this post I will explain some of the simple command line techniques you can use for diagnosing these email issues.

NSLookup

NSLookup is the command line utility for querying the Domain Name System (DNS).  Because email delivery relies so heavily on the Mail Exchanger (MX) records contained within DNS you need to know how to use it for verifying DNS configurations.

When someone reports a problem sending email to an outside party and you want to investigate it one of the first things you’ll need to determine is the name or IP address of their mail server.  This is the job of the MX record, which you can query using NSLookup. Continue reading Diagnosing Email Server Problems with the Windows Command Line

Sending secure email often involves the process of also having to troubleshoot error messages related to TLS and SMTP in Outlook.

Transport Layer Security (TLS) is a cryptographic protocol used to encrypt traffic over networks such as the Internet. Use TLS encryption for servers that require basic authentication. With so much critical information such as usernames and passwords passing through your network, why take the risk that someone snooping could eavesdrop and pull out important corporate information? Implementing encryption and other security measures can help to protect your corporate jewels. The enforcement of security will require users to use the same encryption level that you set when they try to negotiate access to your network and servers. Without the same level of security, messages will be returned and non-delivery reports (NDR) will be generated.

Simple Mail Transfer Protocol (SMTP) is used for sending outgoing mail for both POP and IMAP clients and is well known for its vulnerabilities such as spoofing of emails.

Continue reading Debugging SMTP and TLS errors in Outlook