--- title: "Leveraging Outbound SMTP Proxy Server Can Protect Your Organization From Blacklisting | DuoCircle" description: "Leveraging Outbound SMTP Proxy Server Can Protect Your Organization From BlacklistingSpam email is one of the major causes of phishing attacks and malware" image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/content/outbound-spam-filtering/outbound-smtp-proxy/" --- Content # Leveraging Outbound SMTP Proxy Server Can Protect Your Organization From Blacklisting Leveraging Outbound SMTP Proxy Server Can Protect Your Organization From BlacklistingSpam email is one of the major causes of phishing attacks and malware [ Talk to an Expert → ](/contact/) [ See what we make ](/products/) ## Leveraging Outbound SMTP Proxy Server Can Protect Your Organization From Blacklisting _Spam email is one of the major causes of phishing attacks and malware infections_. These emails are not only harmful to the recipient, but they can also be detrimental to the server they are being sent from. If any spam emails originate from any particular SMTP server or network, it simply means that the authenticity of any email being sent from that network is questionable. _Any email received from such an SMTP server can end up in the trash or spam folder of the recipient_. In the worst-case scenario, they might be filtered by **spam filtering tools**. Using the **SMTP proxy server** along with their actual SMTP server is the solution here for SMTP users. _SMTP proxy server is a relay service that can provide an additional layer of security to any SMTP server while receiving or sending emails_. There are two types of [SMTP proxy service](http://www.aboutmyip.com/AboutMyXApp/SmtpProxy.jsp): ### Inbound SMTP Proxy Server _Inbound SMTP proxy server is used to verify and authenticate incoming traffic_. If any flagged or blacklisted email is received in incoming traffic, then the inbound SMTP [proxy](https://multilogin.com/gateway/residential-proxies/) server can block them before they are received at the actual SMTP server. _Inbound SMTP service protects users against phishing attacks and malicious spams_. It allows users a great deal of safety is the first line of defense. ### Outbound SMTP Proxy Server Similarly, outbound SMTP proxy service is used for checking outgoing traffic. [Outbound spam filtering](/content/outbound-spam-filtering) can be used to make sure any emails sent through the actual SMTP server are already **verified by SMTP proxy**. Therefore, _any spam email is verified before they get to the incoming SMTP server of the recipient_. What makes outbound SMTP proxy server significant is that it allows organizations to maintain the credibility of their SMTP mail servers. _Any email sent from a maliciously infected computer can further spread the infection into the receiver’s computer_. As such, SMTP proxy service allows the sender to maintain authenticity against threats of being blacklisted. There are two types of outbound SMTP filtering, including open source and paid SMTP proxy services. Detailed information about both types are as follows: ### Outbound spam filtering: open source There are [outbound spam filtering open-source](/content/outbound-spam-filtering/outbound-spam-filtering-open-source) SMTP proxy relays that organizations can use with their actual SMTP server. MailCleaner & Proxmox are two such examples that provide **open-source SMTP proxy service**. ### Outbound spam filtering: Office 365 Microsoft owned tool Office 365, allows any user to efficiently utilize outbound spam filter to check and verify any email that is sent through their SMTP server. [Outbound spam office 365](/content/outbound-spam-filtering/outbound-spam-office-365) is an easy tool that can be integrated with the user’s actual **SMTP mail server** for inbound or outbound spam filtering. _Using inbound and outbound SMTP proxy servers is a must for enterprises_. Inbound SMTP proxy service can protect your valuable information systems against any phishing or malicious attacks executed by cyber attackers. Similarly, outbound SMTP proxy service can protect the recipients from any phishing or malicious attacks sent through their network, intentionally or unintentionally. ### Final Words _Once an SMTP server is reported as a malicious outbound server, it can be blacklisted by spam filtering tools_. If the server is blacklisted, a sent email could end up in the [spam folder](https://optinmonster.com/11-reasons-why-your-emails-go-in-the-spam-box-and-how-to-make-sure-they-dont/) of some recipient, which is a grave threat to the organization’s authenticity and brand value. Such blacklisting can also result in reduced sales, inefficient digital marketing, and communication gaps between the sender and the receiver. Using Outbound SMTP Proxy Servers can help you, and your organization avoid this grave risk effectively and efficiently. ##### Join the thousands of organizations that use DuoCircle --- Find out how affordable it is for your organization today and be pleasantly surprised. Interested in our Partner Program for MSPs and VARs? Visit Our [MSP Partner Program](/msp-partner-program). ## Ready to talk? Same-day response from someone technical. We tell you yes or no quickly. If yes, we get to work. [Talk to an Expert→](/contact/)[See what we make](/products/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. We deliver about 90% of category-leader capability at roughly half the price, backed by experts who own the outcome. 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