Hi Guys,
I am monitoring very strange e-mails in my mail queue:

It looks like that they are bounceback e-mails (Mail Delivery System, etc is shown in the body chunk); however they are never delivered to the addresses (they stay in the mail queue and are deleted automatically after some time, or I delete them when I see them).
I think that it is happening because spammers are doing mail forgery (out of my system), which produce those bounceback messages.
Can you give to me a hint how to get rid of these messages? I am on FreeBSD 7.3.
I am monitoring very strange e-mails in my mail queue:

It looks like that they are bounceback e-mails (Mail Delivery System, etc is shown in the body chunk); however they are never delivered to the addresses (they stay in the mail queue and are deleted automatically after some time, or I delete them when I see them).
I think that it is happening because spammers are doing mail forgery (out of my system), which produce those bounceback messages.
Can you give to me a hint how to get rid of these messages? I am on FreeBSD 7.3.