This is a common "technique" of spammers to send out E-Mail. They use a fake "From:" address to send out their E-Mail, to confuse people and hide their true identity. Many times spammers set the From: field to the same address as the To: field, to confuse people into opening the E-Mail or to get around spam filters.
Also, today's newest viruses often grab an E-Mail address from someone's Address Book and use that random address as the From: field, to disguise its nature as a virus or worm.
There is not much that can be done to prevent someone from setting the From: field to your E-Mail address, or an address at your domain. The spammers are not sending out the E-Mail through your account or our mail servers, but simply just putting a fake From: address in their outgoing E-Mails (Similar to someone putting your return address on an envelope and then mailing it via postal mail).
You can tell where an E-Mail actually originated from by looking at the actual Internet headers of an E-Mail. For example, if you use Microsoft Outlook as your E-Mail program, right click on the E-Mail in your Inbox, and select "Options" from the dropdown box. This will show you the true Internet headers and where an E-Mail was actually sent from. In Outlook Express, you would right click on the E-Mail, select "Properties", and then the Details Tab to see the headers.
These headers can be confusing to read, but do contain the actual machines on the Internet as to where an E-Mail originated from. These headers can be used to show that your E-Mail box or mail server was not actually sending out the spam.
If people E-Mail you, angry about spam that seems to have originated from your address, your best course of action is to reply to them and explain that you are also a victim in this spam. You can use the Internet headers to show that it did not originate from your system/computer.
If you are unsure of where an E-Mail actually originated from that contains your E-Mail address, you can send LexiConn a copy of the E-Mail's Internet headers, and we can determine whether the E-Mail was sent from your computer or not.
Your best defense against viruses affecting your network/computer is to maintain an up to date Virus Protection software program, and make sure it is always scanning incoming E-Mail messages, as well as outgoing. In addition, LexiConn offers a spam protection system with virus blocking software that can be installed in your account for a low monthly fee that will help eliminate spam you receive, and block out harmful virus attachments.