Several other mail transfer agents are available to replace sendmail. Two popular aternatives are Qmail (www.qmail.org) by David Bernstein, and Postfix (www.postfix.org) by Wietse Venema. Both of these MTAs were designed and written from the ground up with security and performance in mind. It is beyond the scope of this guide to give details on installing and configuring either of these alternatives, but a wealth of information is available on the Internet.