How to use RBL Servers to block Spam for Free on Mail Servers
In this article we will discuss how to use RBL Servers to block Spam for Free on Mail Servers
First, what is a RBL server? A Real-Time Black List (RBL) is a Domain Name Server (DNS) that contains the IP addresses of SMTP servers that either originate spam, or are considered to be spam open relay hosts. One of the most common methods for sending spam, open relays are servers with insufficient security or other loopholes that allow anyone who knows how to tap into them, and use them for mass mailings of anonymous email.
Fortunately, you can find and use one of several RBL service providers to prevent spam getting in your user’s inbox reject from the start all emails that are sent by compromised spam open relay hosts. This is done by checking the sender’s IP / domain against RBLs
Funniest Spam Ever Sent
We receive spam all the time and it’s such an nuisance, but every once in a while you come across a spam message that is just so ridiculously funny you just can’t help to laugh. These are actual spam emails that made their way into our junk mail folders at work which had us all in stitches. The creative use and misuse of the English language in the context of these spam emails makes them hilarious. Enjoy.
Subject: A Genuine Univers1ty Degree 1n 4-6 weeks!
Have you ever thought that the only thing stopping you from a great job and better pay was a few letters behind you name?
Well now you can get them!
BA BSc MA MSc MBA PhD
Within -46 weeks!
No Study Required!
100% Verifiable!
These are real, genuine degrees that include Bachelors, Masters, MBA and Doctorate Degrees. They are fully verifiable and certified transcripts are also available.
What Can You Do When Your Spam Filter blocks more of the good e-mails?
The war against spam is a cat-and-mouse game with spammers working relentlessly to outwit the spam filters.
Recently, we heard of a story where a law firms’ employees complained to their IT shop that they where getting to much spam even though the IT shop installed and configured spam filters on their email servers. To remedy this problem the IT shop increased filtering and the levels of spam were drastically decreased. But, their was a negative effect. Important emails where not getting through the filers and as a result this wound up costing the law firm money due to missed client appointments.
Their email filters were deleting important emails from clients in what are called false positives. A false positive is where the spam filter takes a negative action on what is really a valid email.
Since spam filters may never be 100% effective it is good practice to quarantine, and not to delete, all e-mails marked as spam into a spam folder. The folder should be accessible to all e-mail users so they can review the list of quarantine emails prior them being deleted.
It may be time consuming for email users to review their spam messages but this practice helps stop the automatic deletion of false positive valid emails.
How to catch sites selling your e-mail address to spammers using Google
If you’re like most people, not a week goes by that you don’t subscribe or enter your email address as part of registering on a new website. However, you have to be careful. Allot of websites are selling email address to spammers. These days we recommend using Google’s Gmail. Gmail has a few nice features which you can use to find out which websites may sell your email address to spammers.
Let’s say you are Tom Barton and you sign up for a Google Gmail account with the address tombarton@gmail.com. With Gmail you could use any of the following addresses and your emails will still arrive to the account tombarton@gmail.com.
TomBarton@gmail.com
tomBarton@gmail.com
Tom.Barton@gmail.com
t.o.mbarton@gmail.com
You can put any number of dots in your email address and it would still go to your primary Gmail account tombarton@gmail.com.
Another interesting feature with Gmail is that you can add text after your Gmail user id with a ‘+”. For example, you could register your email address at a website such as tombarton+website_name@gmail.com where web site name is the name of the website that you are registering your email address. Your conformation will still be forwarded to tombarton@gmail.com because Gmail doesn’t recognize any combination of words or numbers after the “+” sign.
The great part about using Gmail and registering your email address with the add-on of +website_name is that now you catch websites selling your e-mail address to spammers.
How to stop Exchange Server Relay
If you’re a Microsoft Exchange server Admin part of your job is to keep your organization free of SPAM.
Regardless of how much bandwidth your organization may have, there is a finite amount of data that the Internet connection can handle in a given amount of time. This means that if your organization is using their Internet connection at or near its total capacity then any time you receive a junk E-mail message, other legitimate messages are kept waiting until bandwidth becomes available. Additionally, organizations plagued by excessive SPAM, reduces available disk space on an Exchange Server. So as you can see it’s imperative that you effectively combat SAPM.
The Microsoft Exchange Server Internet Mail Service may be configured as a publicly accessible relay mail. In this configuration, the outside users can use the relay Internet Mail Service as an agent for unsolicited commercial e-mail (UCE or SPAM), flooding others with many copies of the same message.
To prevent this from happing, first, make sure that the default SMTP relay settings have been applied to your Exchange 2003 servers per Microsoft’s article on how to configure SMTP relay restrictions. If your Exchange server is still sending SPAM, then you should disable all authentication methods except for “anonymous” on your Internet-facing SMTP host. By default, anonymous authentication, will allow messages to be sent, but not relayed.
If outbound SPAM remains a problem, then the SPAM is coming from one of your internal hosts. You may consider resetting all passwords in your Exchange organization to regain control over the SMTP relaying, or reset the Relay Restrictions tab to “Allow all computers which successfully authenticate to relay, regardless of the list above.”
For more information, read Microsoft’s article, Stop Exchange Server SPAM from the inside by locking down SMTP.
