From AdminWiki

http

• Apache httpd - the swiss army kitchen
• lighttpd - lightweight singlethreaded/singleprocess webserver. ideal for pushing large amounts of traffic.

ftp

• ProFTPD
• vsftpd

smtp

Daemons

• Exim
• Postfix

Blacklists

The bane of every administrator.

• openrbl

imap / pop3 / mail access

• Dovecot
• Courier
• CommuniGatePro (Commercial)

File Sharing

• CIFS and Samba
• NFS

ident

ntp

The NTP Server pool exists which you could use, but shouldn't on production-class systems. Better query one of these instead:

• ptbtime1.ptb.de
• time.nist.gov
• ts1.univie.ac.at