Invalid Email Address

[l5foye]

I use Hotmail (yes, I know) and have been getting a lot of junk mail. When I go to block some of these emails, I get a message 'Invalid Email Address' . My question- how does email arrive with me from an invalid email address? If I use an incorrect email address, I cannot send the email. How do the spammers get round this?

 

[Stratman]

One way is by spoofing the 'from' address. If you run your own email server (easily done) you can simply replace the genuine 'from' address with a fake one. From the spammers point of view this has many advantages, such as the inability of victims to block their spam and to prevent their own inbox being spammed in retaliation.

 

[John]

A lot of spam filters will recognise heuristics of spam, as well as composition and keywords so it will only be a matter of time before they start filtering out automatically.

Normally you can mark emails as spam rather than simply trying to block the address.

This is better as it can be used to improve spam filters by the vendor.

 

[john,cook109]

A while ago my son told me of sites where you may have an e-mail address for 10 mins and then its gone forever. I am not sure if this style of address still exists.

 

[PobodY]

A while ago my son told me of sites where you may have an e-mail address for 10 mins and then its gone forever. I am not sure if this style of address still exists.

*cough* mailinator.com

I use that one every time I have to give someone an email address, but I don't want them to have my real address. - If you know the username you provided you can retrieve messages from the mailbox, but it trashes anything left there for more than a couple of days (if I recall correctly).

As for the "from" address isn't it just a field in the header? Easier to fiddle in Linux probably.

 

[markjay]

One way is by spoofing the 'from' address. If you run your own email server (easily done) you can simply replace the genuine 'from' address with a fake one. From the spammers point of view this has many advantages, such as the inability of victims to block their spam and to prevent their own inbox being spammed in retaliation.

Or - if your ISP provides an authenticated SMTP server (some do some don't), the you can configure your email client (e.g. Outlook) to show whatever email address you like as the sender's email. You can, for example, send outgoing email as [email protected].

In theory Sender Policy Framework (SPF) Record in the DNS should prevent this sort of spoofing, but SPF is not mandatory and many email systems are still not using it.