Troubleshooting ExchangeDefender Delivery | ExchangeDefender [ Skip to content ](#main) [ ![ExchangeDefender](/assets/images/xd_logo_blue.png) ](/) Email Security ![Platform Overview](/assets/images/m-xd-pro.png)### ExchangeDefender PRO Enterprise-grade email security made simple for every business. [Sign Up](/sign-up) [Live Demo](/demo) [Email Security Stops spam, malware & phishing in real time. ](/email-security) [Encryption Secure your emails, attachments & sensitive data. ](/corporate-email-encryption) [Web File Sharing Easy, safe cloud file sharing with access control. ](/web-file-server) [Live Archive Locked-in email backup & continuity during outages. ](/livearchive-backup) [Emergency Inbox Keep email flowing without interruption if your provider fails. ](/inbox) [Spearphish Train your team with phishing simulations & risk tracking. ](/spearphishing) Managed Email ### Enterprise-Grade Managed Email Reliable, secure, and fully managed email operations for modern organizations. ![ExchangeDefender](/assets/images/managed_email_menu.png) [Microsoft365/Google Email Management Expert management and security for Microsoft 365 and Google Workspace email. ](/managed-email-operations) [AI Advisory Secure, practical AI consulting & implementation for SMBs. ](/management-ai) Company ### ExchangeDefender: 29+ Years of Trust We are a cybersecurity company focused on business email protection, with 29+ years of experience keeping organizations secure, connected, and resilient. ![ExchangeDefender](/assets/images/careers_1.png) [ About Us Learn our purpose, values, and the mission behind every decision. ](/about-us) [ Blog News, product updates and email security insights. ](/blog) [ Capabilities Discover the tech and expertise that keep your email secure around the clock ](/capabilities) [ Careers Be part of a team using modern tech to solve real threats and ship great work. ](/careers) [Partners](/partners) [Docs](/docs) [Contact Us](/contact) Talk to a Human Open menu Menu ---- Email Security [Email Security](/email-security) [Encryption](/corporate-email-encryption) [Web File Sharing](/web-file-server) [Live Archive](/livearchive-backup) [Inbox](/inbox) [Spearphish](/spearphishing) Managed Email [Microsoft365/Google Email Management](/managed-email-operations) [AI Advisory](/management-ai) Company [About Us](/about-us) [Blog](/blog) [Capabilities](/capabilities) [Careers](/careers) [Partners](/partners) [Docs](/docs) [Contact Us](/contact) Talk to a Human Search documentation On this page On this page ------------ - [How ExchangeDefender Works](#how-exchangeDefender-works) - [Troubleshooting Outbound Delivery](#troubleshooting-outbound-delivery) - [Local Server](#local-server) - [Check Outbound Smarthost Connectivity](#check-outbound-smarthost-connectivity) - [Troubleshooting Inbound Delivery](#troubleshooting-inbound-delivery) - [General Troubleshooting](#general-troubleshooting) - [Check the DNS](#inbound-check-the-dns) [ Documentation ](https://www-preview.exchangedefender.com/docs) [Documentation](https://www-preview.exchangedefender.com/docs)Troubleshooting ExchangeDefender Delivery ========================================= Troubleshooting ExchangeDefender Delivery. Preface: How ExchangeDefender Works [¶](#how-exchangeDefender-works) ---------------------------------------------------------------------- E-mail delivery problems can be frustrating to deal with but troubleshooting is very quick and easy to isolate. Once the problems are isolated, it is easy to find a solution or at least a workaround to assure timely delivery of email. ExchangeDefender is by nature a “stateless SMTP proxy” that analyzes inbound and outbound mail flow for the presence of potentially dangerous or unwanted content. In plain English, ExchangeDefender sits between you and the Internet and only lets the safe messages and attachments through. Troubleshooting Outbound Delivery [¶](#troubleshooting-outbound-delivery) --------------------------------------------------------------------------- The following instructions can help you troubleshoot outbound delivery and find out why messages you send from your network are not getting to their intended recipients. ### Local Server [¶](#local-server) The first step in isolating an outbound mail problems is to check your own server. Make sure your mail client can connect to the mail server, send a test message and make sure it ends up in the correct queues and is properly dispatched to the smarthost at **outbound.exchangedefender.com**. Your local mail server may have a malfunctioning firewall, stopped services, full hard drives or even be completely offline for routine maintenance or otherwise. If the local mail server is to blame it is likely affecting the entire organization, if it is only affecting a single user the issue is likely local (to the affected account or workstation). If you identify a local problem consult your system administrator. ### Check Outbound Smarthost Connectivity [¶](#check-outbound-smarthost-connectivity) Internet problems can significantly impact your ability to send email. First check that you can actually resolve the address of our SMTP smarthost at outbound.exchangedefender.com and that you can actually connect to it. For this we will use nslookup and ping tools, available at your command prompt. On Windows XP / Server 2003 click on **Start**, **Run**, type in cmd and hit enter. On Windows Vista click on Start, type in cmd and hit enter. **Note:** Telnet client is built into Microsoft Windows XP / Server 2003. On Windows Vista and Server 2008 you must install it from the command prompt. Just type in start /w pkgmgr /iu:”TelnetClient” **Step 1: Check DNS** First, let’s check the DNS to make sure your sever can locate our smarthost, outbound.exchangedefender.com. From the command prompt type in the following: **nslookup outbound.exchangedefender.com** This is what should happen if everything is working properly. You will receive the IP address of outbound.exchangedefender.com on the last line. Proceed to the next step to see if you can connect to our outbound smarthost. C:>nslookup outbound.exchangedefender.com Server: UnKnown **Address: 192.168.1.1:53** Non-authoritative answer: Name: outbound.exchangedefender.com **Address: 65.99.192.91** This is what happens if there is a problem, you will receive **Unknown** followed by the error code. If this happens consult your system administrator for help. C:>nslookup outbound.exchangedefender.com Server: UnKnown **Address: 192.168.1.1:53** *** UnKnown can't find outbound.exchangedefender.com: Non-existent domain **Step 2: Connect to outbound.exchangedefender.com** We will now use telnet to check if you can connect to outbound.exchangedefender.com. From the command prompt, telnet to outbound.exchangedefender.com on port 25 C:>telnet outbound.exchangedefender.com 25 220 outbound.exchangedefender.com ESMTP ExchangeDefender; Fri, 16 Nov 2007 13:20.. If you receive any errors, such as connection failed, connection refused or a very long timeout with eventual disconnection, consult your system administrator. However, if you get the outbound.exchangedefender.com “banner” everything is good so far, continue to step 3. **Step 3: Send a sample email** So far you’ve confirmed that your client is working, that your server is working, that your Internet connection is working and that you can connect to our outbound smarthost at outbound.exchangedefender.com. Now we will try to send a sample email and see if we can get outbound.exchangedefender.com to give us an error. Just type in the fields in the bold and watch the responses: C:>telnet outbound.exchangedefender.com 25 220 outbound.exchangedefender.com ESMTP ExchangeDefender; Fri, 16 Nov 2007 **ehlo scrooge.exchangedefender.com** 250-outbound.exchangedefender.com Hello scrooge.exchangedefender.com \[65.99.255.40\], pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-AUTH LOGIN PLAIN 250-STARTTLS 250-DELIVERBY 250 HELP **mail from: postmaster@exchangedefender.com** 250 2.1.0 postmaster@exchangedefender.com... Sender ok **rcpt to: info@exchangedefender.com** 250 2.1.5 info@exchangedefender.com... Recipient ok **data** 354 Enter mail, end with "." on a line by itself **Subject: outbound.exchangedefender.com test from Vlad** **This is just a test of the outbound.exchangedefender.com system.** **Please ignore.** 250 2.0.0 lAGIVt85032678 Message accepted for delivery Just type in the fields in the bold and watch the responses: Congratulations, you’ve just successfully sent an email. Let’s look at the elements. First line is “ehlo scrooge.exchangedefender.com” where you would have typed the name of your mail server. This helps identify your mail sever to ours and show the commands that are available. Second line, “mail from: postmaster@exchangedefender.com” identifies the sender, this is where you would type in your email address. Third line, “rcpt to: info@exchangedefender.com” identifies the recipient, this is where you should type in the person you are trying to send email to. Fourth line is “data” and it just tells the SMTP server that you are about to send an email. Fifth line provides the subject, “Subject: outbound.exchangedefender.com test from Vlad” followed by the body of the actual message. The last line is just a dot “.” by itself, signifying the end of the message. If all went well, you will receive a message tracking id, in this case: “**lAGIVt85032678**” along with the message “Message accepted for delivery.” Congratulations, everything is working perfectly! ExchangeDefender will now take that message and send it to the remote recipient. **Important Note:** Any errors, bounces or returns you receive via email after you have received “Message accepted for delivery” clearly indicate a problem on the remote server. Because these errors are due to the configuration on the remote server (RBL, network problem, configuration) and thus outside of our control, we will not be able to assist you. Contact the remote server administrator and find out why they are not accepting your messages. Alternately, remove outbound.exchangedefender.com from your smarthost configuration. There is one common error that you may encounter while sending email from your network. That error involves rejected relay right after you provide the recipients email: **rcpt to: remoterecipient@remotedomainuser.com** 550 5.7.1 remoterecipient@remotedomainuser.com... **Relaying denied. Proper authentication required.** The error message “Relaying denied. Proper authentication required” indicates that outbound.exchangedefender.com does not know who you are and you are not in it’s access list. By default ExchangeDefender outbound.exchangedefender.com system will accept messages only from IP addresses that are configured for your server (usually the inbound server IP). If you encounter this error your IP address may have changed or the IP address you are sending messages from is not in our access list. Please consult your system administrator or ExchangeDefender partner or support to make sure the correct IP address is listed in our access lists. **Still not working?** You've tried everything suggested above and it is still not working. Don’t worry, we are here to help. Cut and paste the output from steps 1, 2 and 3 and open up a support request. Our support team can use the output from the troubleshooting steps you have made and pinpoint the problem and help find a solution. Our support portal is at [https://support.ownwebnow.com](https://support.ownwebnow.com), just login, click on **Support**, click on **Create New**, and paste in the contents of your sample email session described in step 3. We look forward to helping you in any way we can! Troubleshooting Inbound Delivery [¶](#troubleshooting-inbound-delivery) ------------------------------------------------------------------------- The following instructions can help you troubleshoot inbound delivery and find out why messages that were sent to you have not arrived in your mailbox. ### General Troubleshooting [¶](#general-troubleshooting) The first step in isolating inbound delivery problems is finding out if the issue only affects you or if it affects the entire organization. Symptoms that affect the entire organization can be the expired domain name, misconfigured firewall, lack or improper IP restrictions, Internet Service Provider issues, router problems, available storage space on the server, expired server antivirus or even stopped services on the server itself. These items tend to be the last ones people check and the most frustrating ones to solve because they generally require a significant amount of time to correct after you have tried everything else. So do yourself a favor and check them first! ### Check the DNS [¶](#inbound-check-the-dns) On Windows XP / Server 2003 click on **Start**, **Run**, type in cmd and hit enter. On Windows Vista click on **Start**, type in cmd and hit enter. Note: Telnet client is built into Microsoft Windows XP / Server 2003. On Windows Vista and Server 2008 you must install it from the command prompt. Just type in start /w pkgmgr /iu:”TelnetClient” **Step 1: Check DNS** First, let’s make sure that your domain name is properly configured to send mail through ExchangeDefender. From the command prompt type in the following: **nslookup –q=mx yoursampledomain.com** If you are correctly configured, you will receive the following response: Microsoft Windows \[Version 6.0.6000\] Copyright (c) 2006 Microsoft Corporation. All rights reserved. C:>**nslookup -q=mx yoursampledomain.com** Server: UnKnown Address: 192.168.1.1:53 Non-authoritative answer: **yoursampledomain.com MX preference = 10, mail exchanger = inbound30.exchangedefender.com** yoursampledomain.com nameserver = ns1.ownwebnow.com yoursampledomain.com nameserver = ns2.ownwebnow.com If you see the above, you are all good, proceed to step 2. If you see additional MX records, such as failover and secondary MX records you need to remove them before you continue. If you do not see inbound30.exchangedefender.com anywhere in this display, you are not configured to use ExchangeDefender, consider our deployment document available under the Support link at [https://exchangedefender.com/docs/exchange-deployment-guide](https://exchangedefender.com/docs/exchange-deployment-guide) **Step 2: Check your mail server and IP restrictions** Second step in verifying your inbound settings is to check that your mail server is properly configured to accept connections. This is a comprehensive process with full details available on our ExchangeDefender web site http://www.exchangedefender.com/documentation From your mail server console, try to connect to port 25. You should be able to obtain a connection. From the command prompt, type in the following: **C:>telnet localhost com 25** 220 scrooge.exchangedefender.com Microsoft ESMTP MAIL Service ready at Fri, 16 N ov 2007 14:16:42 -0500 You should see your servers SMTP banner which means you are able to connect to your server and it is ready to accept mail via SMTP. If it is not, check SMTP services and make sure they are started. Then check IP restrictions and IP configuration. If possible, check that you can connect to this server from a remote network. Frequent causes of inbound problems tend to be related to the Internet Service Provider quality of service, unstable connection, packet loss, latency and so on. ExchangeDefender functions as a proxy mail server, so if it cannot establish a solid connection to your mail server it cannot send you mail. Finally, check the IP address restrictions as per our deployment guide at [https://exchangedefender.com/docs/exchange-deployment-guide](https://exchangedefender.com/docs/exchange-deployment-guide) - incorrect IP restrictions can lead to delays in email delivery. **Step 3: Send a sample message to yourself** So far you have confirmed your configuration. Your mail server is up and accepting connections, it is configured to use ExchangeDefender and everything checks out. Time to send a test message to yourself through ExchangeDefender. Just type in the fields in the bold and watch the responses: C:>telnet inbound30.exchangedefender.com 25 220 inbound31.exchangedefender.com ExchangeDefender 3; Fri, 16 Nov 2007 14:21:47 **ehlo scrooge.exchangedefender.com** 250-inbound31.exchangedefender.com Hello scrooge.exchangedefender.com \[65.99.255.40\], pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-AUTH LOGIN PLAIN 250-STARTTLS 250-DELIVERBY 250 HELP **mail from: me@mysamplecorporatedomain.com** 250 2.1.0 me@mysamplecorporatedomain.com... Sender ok **rcpt to: me@mysamplecorporatedomain.com** 250 2.1.5 me@mysamplecorporatedomain.com... Recipient ok **data** 354 Enter mail, end with "." on a line by itself **Subject: ExchangeDefender test from Vlad This is just a test of the inbound30.exchangedefender.com system.** **Please ignore.** 250 2.0.0 lAGIVt85032678 Message accepted for delivery You have just successfully sent an email to yourself through ExchangeDefender, congratulations. If all works out well, you will receive your email in a moment. If you don’t, consider the possible issues: **Step 4: When it doesn't work** If the mail does not arrive, or does not arrive in timely manner, you can count on us to help you figure out what the problem may be. Here are some possible symptoms along with the course of action **Problem: Email arrives, but is delayed minutes or hours..** **Solution:** Open a support request at https://support.ownebnow.com and paste in the contents of step #3. **Problem: Email never arrives..** **Solution:** First, check that the message has not fallen into the SPAM or SureSPAM quarantine. Second, check that the IP address configuration is correct, if your IP address has changed or if your configuration to the SMTP server or firewall has changed significantly the message may be spooling on our servers. Finally, if none of the above applies, open a support request at https://support.ownwebnow.com and paste in the contents of step #3. **Problem: Email from remote recipient does not arrive** **Solution:** Proceed to step #5 **Step 5: When it doesn’t work from remote senders** Remote troubleshooting of ExchangeDefender is identical to step #3 that you completed to make sure sample messages get through ExchcangeDefender and to your mailbox. If you can get past step #3 successfully, you can proceed to remote troubleshooting, that is, making sure that the remote sender can connect to ExchangeDefender and successfully relay mail. Instruct them to do the following, replacing senderaddress and recipientaddress with their email address and your email address, respectively. C:>telnet inbound30.exchangedefender.com 25 220 inbound31.exchangedefender.com ExchangeDefender 3; Fri, 16 Nov 2007 14:21:47 **ehlo someremotemailserver.com** 250-inbound31.exchangedefender.com Hello someremotemailserver.com \[1.2.3.4\], pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-AUTH LOGIN PLAIN 250-STARTTLS 250-DELIVERBY 250 HELP **mail from: senderaddress** 250 2.1.0 senderaddress .. Sender ok **rcpt to: recipientaddress** 250 2.1.5 recipientaddress.. Recipient ok **data** 354 Enter mail, end with "." on a line by itself **Subject: ExchangeDefender Remote Test This is just a test of the inbound30.exchangedefender.com system. Please ignore.** 250 2.0.0 lAGIVt85032678 Message accepted.. Open the support ticket at [https://support.ownwebnow.com](https://support.ownwebnow.com) and we will get to the bottom of it. Once we have the message ID we can track it through our system. If you are an ExchangeDefender Service Provider you can use the messageid (long string on the last line of the SMTP conversation) to track the message progress through ExchangeDefender. If all else fails, open the support request at[ https://support.ownwebnow.com](https://support.ownwebnow.com) pasting in the contents of Step #3 and Step #5. These are the very minimum pieces of information we need in order to track the message and isolate the issue. Solutions --------- - [Stop Spam & Malware](/email-security) - [Hands-Free Email Backup](/livearchive-backup) - [Instant Email Recovery](/inbox) - [Send Private Emails](/corporate-email-encryption) - [Train Against Email Threats](/spearphishing) - [Share Files Safely](/web-file-server) Company ------- - [About ExchangeDefender](/about-us) - [Compliance & Legal](/our-compliance) - [Become a Partner](/partners) - [Support Portal Login](https://support.exchangedefender.com/) - [Microsoft 365 Email Management](/managed-email-operations) - [AI Advisory Service](/management-ai) ![ExchangeDefender](/assets/images/dark-xd-logo.png)USA: +1 (407) 465-6800 United Kingdom: 0800 8620149 Australia: +61 0390010641 Fax: +1 (954) 839-8737 [ ](https://www.facebook.com/ExchangeDefender) [ ](https://www.twitter.com/XD_Defender) [ ](https://www.linkedin.com/company/exchangdefender) [ ](/blog) © 2026 Own Web Now Corp - All rights reserved </> with ❤️ in Orlando [SLA](/sla) [TOS](/tos) [PRIVACY](/privacy-end-users) [AUP](/aup) We're Here to Help 👋 -------------------- Tired of AI 🤖 and hold music? Request a call or text (sms/telco charges may apply) and someone with a brain and a pulse will get in touch with you promptly. Close modal Website Name Email Address Company Phone Preferred Contact Method Text me Call me Call Date Call Time Time Zone Eastern Central Mountain Pacific London Paris Madrid Berlin Tokyo Dubai Sydney Request Human Contact Submitting... Close Start Your Free Year -------------------- Enter your details and we will set up your free year of email protection. Close modal Website Full Name Email Continue Submitting... Close Try ExchangeDefender for Free 💰 ------------------------------- We look forward to helping you secure your email. We offer a free 30-day no-risk trial, just fill out the form below and one of our onboarding techs will get you started. If you'd just like to take a look at the demo, click here for a [live demo site](/demo). Close modal Website Name Email Address Company Phone Preferred Contact Method Text me Call me Call Date Call Time Time Zone Eastern Central Mountain Pacific London Paris Madrid Berlin Tokyo Dubai Sydney 💰 Get your free month Submitting... 🏃 Explore a Live Demo Submitting... Close Train Your Team Before the Hackers Do 👋 --------------------------------------- ExchangeDefender Spearphish is our new phishing simulation and training tool, designed to help your team spot scams before they click. Want to be first in line? Request early access or get a personal demo — just drop your name and email below. Close modal Website Name Email Address Company Phone Preferred Contact Method Text me Call me Call Date Call Time Time Zone Eastern Central Mountain Pacific London Paris Madrid Berlin Tokyo Dubai Sydney Request Early Access Submitting... Close