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eMail server security Blogs


cPanel spam mitigation – How we fight spamming in cPanel servers

Spam mails are more than a mere nuisance for web hosts. When a server is spammed, valid mails get lost or delayed indefinitely in the pool of spam mails.

Equally panicky situation is outbound spamming from your server. Your mail server IP can easily get blacklisted, causing email delivery failures for your customers.
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How to fix ‘SMTP AUTH is required for message submission on port 587’ error in cPanel/WHM servers

Mail servers have an SMTP authentication feature enabled in them, to validate users who try to send mails through that server.

The ‘SMTP AUTH’ error usually happens when users try to send mails without properly authenticating their mail account in email clients such as Outlook or Thunderbird. (more…)

Email blacklist removal – How to stay off blacklists for uninterrupted mail service

Email blacklist removal – How to stay off blacklists for uninterrupted mail service

Getting listed in a spam blacklist is a dreadful experience for server owners. Users end up facing email delivery failures and bounces, which can take your business reputation for a toss.

As a security measure, mail from blacklisted IPs are rejected by most mail servers. So, if you want uninterrupted mail services, you’ll need to stay clear of blacklists.

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How to fix clamav update database error

How to fix clamav update database error

In our role as Outsourced server support specialists for web hosts, we secure and maintain the servers from attacks and viruses. There are several tools that come in handy, for securing various services.

ClamAV is an open source email scanning program that has an antivirus engine for detecting trojans, viruses, malware & other malicious threats in emails. ClamAV is usually integrated along with popular mail servers such as Exim.

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Top 5 reasons for ‘exim has failed’ error in cPanel servers and how to fix them

Top 5 reasons for ‘exim has failed’ error in cPanel servers and how to fix them

cPanel/WHM is the most commonly used control panel in hosting industry. In our role as outsourced hosting support specialists for web hosting companies, we resolve many errors related to the control panels.

Using the WHM, it is easy manage various services in the server, but there are many situations where these features fail or give errors, and expert intervention is required. (more…)

Linux SMTP relay – How we protect your mail servers from being open relays

Linux SMTP relay – How we protect your mail servers from being open relays

Protecting mail servers from being used as Linux SMTP open relays, is a major security task we perform as a part of our Dedicated Tech Support services for web hosting providers.

An open mail relay is an SMTP server that allows any host to send mails through it. If it is open relay, users can send mails through that Linux SMTP relay server without authenticating.
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How to resolve ‘Outlook cannot connect to SMTP server’ error

How to resolve ‘Outlook cannot connect to SMTP server’ error

Often web hosts get contacted by account owners who are unable to send or receive emails via Outlook. The error message they see in their Outlook would be:

Task 'account@domain.com - Sending' reported error (0x80042109) :  "Outlook cannot connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator or internet service provider (ISP)."

In our role as Website Support for web hosting companies, this is a concern we quickly resolve for users who have email accounts hosted in the customers’ servers.  (more…)

How to fix error “454 4.7.1 Relay access denied” in Postfix mail servers

How to fix error “454 4.7.1 Relay access denied” in Postfix mail servers

454 4.7.1 <user@domain.com>: Relay access denied

This is a commonly seen email failure error by web hosts, website owners and server owners who run Postfix mail server. 454 error usually happens while sending to and receiving from external domains.

In our role as Hosting Support Engineers for web hosting companies, we handle many such mail errors and fix them. Here, we’ll see what causes “454 4.7.1 Relay access denied” error and how we fix it. (more…)

Gmail blacklist removal for your mail servers

Gmail blacklist removal for your mail servers

550-5.7.1 [203.**.**.**] Our system has detected an unusual rate of
550-5.7.1 unsolicited mail originating from your IP address. To protect our
550-5.7.1 users from spam, mail sent from your IP address has been blocked.

Many often, you’d have had your customers complain that their mails to gmail accounts are not getting delivered, but instead getting bounced like this. You’re not the only one facing this issue.

Mail bounces due to gmail blacklisting is a common issue faced by web hosts around the world. In our role as Outsourced Support Specialists for web hosting providers, we often perform gmail blacklist removal for our customers’ servers. (more…)

How to prevent SpamHaus SBL (Spamhaus Block List) blacklisting in web hosting servers

How to prevent SpamHaus SBL (Spamhaus Block List) blacklisting in web hosting servers

554 5.7.1 Service unavailable; Client host [154.0.***.**] blocked using zen.spamhaus.org; https://www.spamhaus.org/sbl/query/SBL289647
SMTP error from remote mail server after pipelined DATA:
    550-197.242.**.*** listed at zen.spamhaus.org

You’d seen these error messages in your mail server, if your IP address has ever got listed in Spamhaus SBL. Getting blacklisted in SBL is a concern for many web hosts, as it often leads to customer complaints about mail delivery failures.

Our engineers fix Spamhaus issues everyday in their role as Outsourced Support Specialists for web hosting providers. Since Spamhaus checks only for their SPAM criteria, we’ve seen that even perfectly legitimate business mails were tagged as spam. (more…)

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