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Showing posts with label bypassing spamfiltersReverse DNS. Show all posts
Showing posts with label bypassing spamfiltersReverse DNS. Show all posts

November 24, 2007

Tips To Increase your email delivery

Ensuring that your email ultimately gets delivered to the end user or the person to whom it is intended in one of the greatest challengers for Online Media Companies. With over 60% of emails labelled as spam . Having a robust technology to beat ISP's stringest policies and beating spam filters is a must to get a high open rate for your email campaign . Ensuring permission-based email is delivered to recipients' inboxes requires an equal amount of effort on marketing and technical front.

1)Create a reverse DNS. Make sure your outgoing mailing IPs have valid RDNS (reverse DNS) entries set up. This ensures when a receiving email server checks who owns the IP trying to connect to it, you'll come up as the result, passing one of the many basic checks ISPs do to deter spammer.# For delivering to AOL you need to make sure your SMTP service's domain can be verified using a reverse DNS lookup. Check with your webmaster or host provider. For more information on this topic check out:

1. www.dnsstuff.com/info/revdns.htm
2. http://ezine-tips.com/articles/resources/20010817.shtml


2)Set up an SPF: SPF (define) is an additional step to verify an email sender's identity. SPF adds another layer of authentication to your outgoing email and protects against phishing (define) attacks on your brand. Some ISPs, such as AOL, require SPF to be implemented to be considered for their white lists. SPF can be used to stop spam from being sent using unauthorized domain names. However, it should be noted that SPF only stops the spammer from forging the “From” field in the e-mail and does not stop the spammer from sending e-mails from a domain in which it is a member.

3.)Make only one connection. When connecting to an email server, send only one message per connection. Some systems still try to shovel as many messages through one connection as possible, akin to throwing 500 email addresses into the BCC field. ISPs frown on this technique, as spammers who want to get as many messages in before being blocked typically use this approach.

4.)Limit Email sending rate. Just because you can send a million messages per hour doesn't mean doing so is prudent. Large spikes in traffic can be seen as dictionary (define) or denial of service (define) attacks. Though the ideal send volume depends on the list's nature (e.g., B2C or B2B), a good rule of thumb is to limit your transmission to 150-200K messages per hour. Keep in mind you will also need to accept feedback in the form of bounced messages; your outgoing speed shouldn't hamper your ability to receive bounces.

5)Accept bounces.: Some email systems, especially older ones, have a nasty habit of rejecting bounce messages. These "bounced bounces" arrive at the receiving ISP and can raise red flags. Nothing irks an ISP more than sending a response that a recipient doesn't exist, only to have the notification rejected and the mailings continue.

6)Validate HTML content: One of the dirtiest tricks in a spammer's arsenal is invalid, broken, and malicious HTML code, used to obfuscate his payload. If you use HTML in your messages, make sure your code is error-free and follows W3C HTML guidelines.

7)Avoid scripting: Security risks due to script vulnerabilities in email browsers have increased over the years. The result is most scripts, such as JavaScript and VBScript, are stripped out of messages. Some email systems reject messages outright if scripting is detected. For greatest compatibility, avoid using scripts in messages. Instead, drive your readers to your Web site, where dynamic components are easily rendered.

8) Avoid AOL 9.0 and MS 2003 image filter issues : AOL has recently released the newest version of its product, AOL 9.0. AOL is anticipating that 30 - 50% of their current customers will upgrade to 9.0 before year end. To protect users from receiving SPAM, AOL has put some measures in place that will affect how your message is received by your AOL subscribers. All graphics will be blocked from being displayed in HTML emails, and links will be deactivated for any new message sent to an AOL 9.0 inbox. When an email is received in AOL 9.0, users will have to click a link at the top of each message (Show Images & Enable Links) to view any graphics within your email. If this action is not taken, images and links will not be displayed or enabled. This is the default setting for AOL 9.0, however, the email recipient does have the ability to add the sender's From Address into their address book (which AOL classifies as People I Know). Once this has been done, all emails received from this address in the future will automatically have images and links showing correctly.

How to ensure that your message is displayed properly?

Your recipients must add you to their address book as a sender they recognize and approve. You should add a line to the top of your email which states something like: "Attention AOL 9.0 users - please add fromaddress@company.com to your address book so that you can see all of our message." Alternatively you can use the override feature in Broadcast to only send a text version of the message to AOL clients. For more information on this issue visit: http://library.marketingsherpa.com/barrier.cfm?CID=2455%20

MS 2003 will also filter the images. For more information visit: http://ktdcommunications.com/communications/katydid_023.htm

9)Be knowledgeable about where you are being blocked - Use a product like Blacklist Monitor to find out where you might be blacklisted. If you are blacklisted, ISPs who check these lists may not deliver your message to the recipient. You need to know where you are blacklisted and how to get delisted. AOL rejects up to 80% of the messages it receives. As many as 30% of your messages may not be delivered if you are blacklisted. Blacklist Monitor (www.blacklistmonitor.com) can tell you where and when you are listed, and provide tips on getting delisted.

10) Avoid being dumped into spam or bulk filters.

a)Use a product like Broadcast that conforms to standard protocols for message delivery
b)If you are sending a newsletter place the word "newsletter" and the date (including month) in the subject line. This reduces your spam score
c)Ensure each message contains an unsubscribe statement that links to a valid URL or a valid Mailto: link. However do not use the words "to unsubscribe" as these are now getting filtered. Use something like "to leave"
d)Do not include .exe or attachments in your message
e)Do not purchase lists
f)Do not rent lists that are not double-opt-in
g)Remind people of their relationship with you. Tell them in the message the email address that they used when they subscribed
h) Include a correct reply email address and telephone contact information in each email
i)Avoid sending long text articles
j)Do not send HTML messages without text alternatives. This can be accomplished in Broadcast by using the "Both" options and creating both a text and HTML version
k)Avoid sending messages with a large number of hotlinks
l) Do not use BCC distribution methods with more than 10 names per email. Use a product like Broadcast that creates an individual message for each email
m)Watch your email lists, heavy B2C distribution to @aol.com, @hotmail.com. @msn.com etc may be flagged
n)Avoid using words or phases that trigger spam filters. For more information on trigger words also visit: http://www.doctorebiz.com/06/021106b.htm and http://www.wilsonweb.com/wmt8/spamfilter_phrases.htm
o) Check out the common tests that filters like Outlook and SpamAssassin use to filter your emails and try to avoid. outlook filters/SpamAssassin tests
p) Routinely check http://www.spamcop.net/ to see if you have been blacklisted unfairly. Send an email to have this rectified. They are quite responsive. To check their list enter: http://spamcop.net/bl.shtml?111.111.111.11 (where 111.111.111.11 is the IP address of your sending SMTP)
q)Sending your delivery in small batches of 500 or less might avoid filtration. This can be accomplished easily by modifying your delivery options within Broadcast
r) A practical guide on avoiding spam filters can also be found from Marketing Sherpa

11)Distributed content filters. Several anti-spam companies help ISPs and enterprise customers cope with the influx of unsolicited email. Brightmail and Postini are two leaders in this field.

12)Using Public list. Publicly accessible blacklists and whitelists, maintained by volunteers, are often used by smaller ISPs and companies without dedicated email administrators. The most widely used lists are Mail Abuse Prevention System (MAPS), SpamCop, Spamhaus, and Spam Prevention Early Warning System (SPE)WS. SPEWS.org - www.spews.org/ ORDB.org - Open Relay Database - www.ordb.org/Listing criteria can be reliable or near capricious, depending on the list owner's preferences. Administrators select the lists that most closely match their company's policy.