It depends how big your company is. For small to medium size businesses there's nothing you can do about a DoS as you need bandwidth coming out of your ears. The solution I would tend to go for is direct all your traffic through your service provider (ie a smarthost) and let them deal with the DoS issues. If you deny all SMTP traffic except from the smarthost on your outer firewall it also deals with the open relay issue. SMTP doesnt have much in the way of secure communication unless you use something like PGP, but that requires the receiving clients to support it too. If its sensitive information passing between remote offices or businesses you deal with on a day to day basis then a secure connection such as VPN would probably be better. Charles Cresswell, IS Manager 020 72130728 The Association of Corporate Treasurers Ocean House 10/12 Little Trinity Lane London EC4V 2DJ tel: +44.(0)20 7213 9728 fax: +44.(0)20 7248 2591 www: http://www.treasurers.org Notice of Confidentiality This e-mail (and any attachments) is intended for the named addressee(s) only. It contains information that may be confidential. Unless you are the named addressee (or authorised to receive it for the addressee) you may not read, copy, use, or disclose it to anyone else. Unauthorised use, copying or disclosure is strictly prohibited and may be unlawful. If you have received this transmission in error, please notify the sender by telephone immediately 020 7213 0705 and delete the message from your e-mail system. The Association of Corporate Treasurers may monitor outgoing and incoming e-mails and other telecommunications on its e-mail and telecommunications systems. By replying to this e-mail you give your consent to such monitoring. The Association of Corporate Treasurers is a company limited by guarantee. It is registered in England at the above address, registration number 1445322. #ACT# The Association of Corporate Treasurers Ocean House 10/12 Little Trinity Lane London EC4V 2DJ tel: +44.(0)20 7213 9728 fax: +44.(0)20 7248 2591 www: http://www.treasurers.org Notice of Confidentiality This e-mail (and any attachments) is intended for the named addressee(s) only. It contains information that may be confidential. Unless you are the named addressee (or authorised to receive it for the addressee) you may not read, copy, use, or disclose it to anyone else. Unauthorised use, copying or disclosure is strictly prohibited and may be unlawful. If you have received this transmission in error, please notify the sender by telephone immediately 020 7213 0705 and delete the message from your e-mail system. The Association of Corporate Treasurers may monitor outgoing and incoming e-mails and other telecommunications on its e-mail and telecommunications systems. By replying to this e-mail you give your consent to such monitoring. The Association of Corporate Treasurers is a company limited by guarantee. It is registered in England at the above address, registration number 1445322. #ACT#