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You should also fix the permissions on the directory hierarchy in such a waythat anonymous users have read-only access to etc and pub directory, and writepermission on the incoming directory.# cd ~ftp# rm .*# mkdir etc pub incoming# chown –R root:wheel /home/ftp# chmod 755 etc pub# chown –R nobody incoming# chmod 5777 incomingAnd this is finally how the directory structure should look like (note the ownersand permissions):# ls -ltotal 6drwxr-xr-x 2 root wheel 512 Nov 9 13:02 etcdrwsrwxrwt 2 nobody wheel 512 Nov 9 13:01 incomingdrwxr-xr-x 2 root wheel 512 Nov 9 12:38 pubChapter 13So the anonymous user (actually the "ftp" user that you have created earlier) hasread-only access to the pub directory (according to file permissions), and also writepermission on the incoming directory. However, the files written in the incomingdirectory cannot be removed or modified by anonymous users later on.Always make sure that the files have correct permission (owner and mod)under the FTP directory hierarchy to prevent security breaches.MailThe Mail Transfer Agent (MTA) is the daemon in charge of transferring electronicmails from one host to another, using the SMTP protocol (RFC 2821 and manyother complementary RFCs). Just like other core Internet services, FreeBSD 7 hasSendmail 8.14.1 bundled in the base system. Sendmail is one of the oldest and widelyused MTAs and is the default MTA on most of the UNIX based operating systems.Besides sendmail, there are other MTAs available, such as Postfix and Qmail, thathave even more advanced features, security and robustness. However the systemadministrators can choose any MTA that suits their specific applications.[ 223 ]