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Spam, Barracuda, and ethics (lack thereof)

One of our clients sent us an email this morning letting us know that they couldn’t send an email to a client. They forwarded the bounce message to us (below) 12.149.35.75 does not like recipient....

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Spam from Live.com

We’re seeing a huge recurrence of spam thats been getting through our spam filters., all coming from @live.com addresses. I hadn’t seen any personally until one of our clients brought up the fact that...

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How to setup fail2ban to block vpopmail attacks

As the Wiki for fail2ban is a little less than explanatory than it could be (and they reversed my edits which made the instructions clearer), here are my own notes on setting up fail2ban to block pop3...

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Of Qmail, Zombies and qmail-remote timeout issues.

Occasionally even in a well maintained system, qmail has issues. One semi-common issue I get to see, is when a server we send mail to doesn’t timeout. This ties up an outgoing mail slot. Over a period...

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Email troubleshooting – a detective story.

As our clients probably know, we run our own email servers. Email is one of those things that looks simple on the surface, but isn’t necessarily so simple when it comes down to troubleshooting. As is...

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simscan and vfork issues

While I usually am good at finding issues relatively quickly, I spent roughly 5 hours troubleshooting an issue today with incoming mail scanning. What was the issue we were seeing? Mail would randomly...

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DMARC support implementation for Computer Solutions

As we’re a pro-active sort of ISP, we often take a look at ways to improve things for clients under the hood. One of those improvements, was our recent DMARC implementation for our mail servers. DMARC...

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Spam and Rules at Computer Solutions

As one of the main contention points people have with mail service is either the amount of spam they receive, or the amount of legitimate email we block, we’ve decided to put the solution in your...

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RoundCube login attack prevention with Fail2ban

I’ve noticed a little spate of password attack attempts via Roundcube – a webmail program we use for mail over at https://mail.computersolutions.cn Roundcube does have captcha plugins available which...

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Gmail (and other google hosted mail) delivery issues

Update Google has added another MX (mail server) for Google Hosted mail – alt4.gmail-smtp-in.l.google.com. This does not currently appear to be blocked (unlike their other 4 MX servers), so we have...

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Google mail issues from China (again)

Some of our clients are experiencing delivery issues to some domains that use Gmail/Google for their email. I previously covered that here –...

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SSL Updates

The SSL certificate for the all servers have been updated to use a wildcard certificate. We *finally* changed over to use a wildcard cert, as pricing has come down enough to not warrant having separate...

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Issues sending to Outlook.com hosted addresses

We are currently seeing some issues sending TLS encrypted mails to Outlook.com hosted email addresses. This appears to only be affecting some of the Outlook.com hosted server ip addresses...

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