by dabempire | Feb 26, 2011 | E-Mail, Knowledgebase
Some users think that by setting up aliases like companyA@yourdomain.com and companyB@yourdomain.com they will be able to catch the spammers if that email address starts to receive spam. This is a myth that by setting up aliases you can catch them. You can not because even if they do not sell your email address to spammers, your email address can go into the hands of spammers. This is what many of the trojans/worms do. They collect email addresses right off your hard drive / addressbook / email software. If not yours, someone you emailed from that email address, their computer may be infected with such worm, and you have no control over that. So it is just a waste of time to set up such aliases. If you ever use an email address, chances are that email address will go into spammers database. You need to use anti-spam techniques like SpamAssassin to filter spam. By increasing email aliases, you are just increasing email traffic (i.e. spam) to your...
by dabempire | Feb 26, 2011 | E-Mail, Knowledgebase
The default email address will “catch” any mail that is sent to an invalid email address for your domain. All mail that is sent to an address that does not exist as pop3 or forwarder will go to the default email address. We strongly recommend that you setup Default Address to :fail: (including colons on both sides of fail) This will make your domain safe from dictionary attacks where spammers send millions of emails addressed to random addresses on your domain. NOTE: This :fail: does not bounce emails. It rejects the email at smtp even before receiving emails i.e. when the sending server starts communicating with the mail server on your account, it asks to deliver email to a certain address. If that address does not exist, it will not accept the email. This way the email will stay in sender’s (or spammer’s) mail queue and will not leave it. So this is not a bounce and the server has not much work to do in this case. On a related note, if it was a bounce, it would bounce to spoofed address and cause more trouble, hence the challenge-response type of anti-spam feature is fundamentally...
by dabempire | Feb 26, 2011 | E-Mail, Knowledgebase
For our shared/sdx/reseller hosting, and users with cpanel on their vps/dedicated, the maximum email size is 50MB. This is the default set by the developers of mail server and they say it is safe value. Anything higher than that can be abused for denial of service. Note: 50MB does not mean you can attach exactly 50MB file. The file attachment is encoded for email transmission and can take more space. For example, a 10MB file may take 12MB in email after encoded data. If you need to send/receive large files, please use...
by dabempire | Feb 26, 2011 | E-Mail, Knowledgebase
This is a new feature of yahoo mail. It is using what is called Grey Listing to fight spam. For more details, you can read: http://en.wikipedia.org/wiki/Greylisting What happens is that whenever a new message is sent to yahoo, it replies with “try again later” message. e.g. here is a test smtp connection to one of the yahoo’s mx: # telnet 66.196.97.250 25 Trying 66.196.97.250… Connected to 66.196.97.250. Escape character is ‘^]’. 421 Message from (a.b.c.d) temporarily deferred – 4.16.50. Please refer to http://help.yahoo.com/help/us/mail/defer/defer-06.html Connection closed by foreign host. Now as you can see, yahoo did not even give us (the ip of a.b.c.d) a chance to start the smtp session. What it will do is wait for us to try again later. Our mail servers (or yours on your vps/dedicated server) will try again later and if yahoo likes the delay long enough, it will let the server communicate further and deliver the email. To avoid such delays and problems with yahoo mail, you are encouraged NOT TO FORWARD emails to yahoo or any other ISP. Please refer to this KB as well why we are saying that:...
by dabempire | Feb 26, 2011 | E-Mail, Knowledgebase
‘Your outgoing (SMTP) e-mail server has reported an internal error. If you continue to receive this message, contact your server administrator or Internet service provider (ISP). The server responded: 503 valid RCPT command must precede DATA’ This error usually means that you are not using SMTP authentication. Please make sure to activate SMTP authentication in your email software. If you are using Outlook express, you can activate SMTP authentication by following these steps: 1. Menu : Tools : Accounts 2. Select Mail tab and highlight the account and click on Properties 3. Select Servers tab 4. At the bottom of it, you can find “My server requires authentication”, select it 5. Press Apply, OK and Close. If you are using MS Outlook, follow these steps: 1. Menu: Tools : Email Accounts 2. View of change existing e-email accounts, press Next 3. Hightlight the email account, and click the button “Change…” 4. Click the button “More Settings …” 5. Select the “Outgoing Server” tab and select the “My outgoing server (SMTP) requires...
