# # hosts.allow access control file for "tcp wrapped" applications. # $FreeBSD: src/etc/hosts.allow,v 1.8.2.7 2002/04/17 19:44:22 dougb Exp $ # $DragonFly: src/etc/hosts.allow,v 1.4 2008/08/10 21:29:16 hasso Exp $ # # NOTE: The hosts.deny file is deprecated. # Place both 'allow' and 'deny' rules in the hosts.allow file. # See hosts_options(5) for the format of this file. # hosts_access(5) no longer fully applies. # _____ _ _ # | ____| __ __ __ _ _ __ ___ _ __ | | ___ | | # | _| \ \/ / / _` | | '_ ` _ \ | '_ \ | | / _ \ | | # | |___ > < | (_| | | | | | | | | |_) | | | | __/ |_| # |_____| /_/\_\ \__,_| |_| |_| |_| | .__/ |_| \___| (_) # |_| # !!! This is an example! You will need to modify it for your specific # !!! requirements! # Start by allowing everything (this prevents the rest of the file # from working, so remove it when you need protection). # The rules here work on a "First match wins" basis. ALL : ALL : allow # Wrapping sshd(8) is not normally a good idea, but if you # need to do it, here's how #sshd : .evil.cracker.example.com : deny # Protect against simple DNS spoofing attacks by checking that the # forward and reverse records for the remote host match. If a mismatch # occurs, access is denied, and any positive ident response within # 20 seconds is logged. No protection is afforded against DNS poisoning, # IP spoofing or more complicated attacks. Hosts with no reverse DNS # pass this rule. ALL : PARANOID : RFC931 20 : deny # Allow anything from localhost. Note that an IP address (not a host # name) *MUST* be specified for portmap(8). ALL : localhost 127.0.0.1 : allow ALL : my.machine.example.com 192.0.2.35 : allow # To use IPv6 addresses you must enclose them in []'s ALL : [fe80::%fxp0]/10 : allow ALL : [fe80::]/10 : deny ALL : [2001:db8:2:1:2:3:4:3fe1] : deny ALL : [2001:db8:2:1::]/64 : allow # Sendmail can help protect you against spammers and relay-rapers sendmail : localhost : allow sendmail : .nice.guy.example.com : allow sendmail : .evil.cracker.example.com : deny sendmail : ALL : allow # Exim is an alternative to sendmail, available in the pkgsrc tree exim : localhost : allow exim : .nice.guy.example.com : allow exim : .evil.cracker.example.com : deny exim : ALL : allow # Portmapper is used for all RPC services; protect your NFS! # (IP addresses rather than hostnames *MUST* be used here) portmap : 192.0.2.32/255.255.255.224 : allow portmap : 192.0.2.96/255.255.255.224 : allow portmap : ALL : deny # Provide a small amount of protection for ftpd ftpd : localhost : allow ftpd : .nice.guy.example.com : allow ftpd : .evil.cracker.example.com : deny ftpd : ALL : allow # You need to be clever with finger; do _not_ backfinger!! You can easily # start a "finger war". fingerd : ALL \ : spawn (echo Finger. | \ /usr/bin/mail -s "tcpd\: %u@%h[%a] fingered me!" root) & \ : deny # The rest of the daemons are protected. ALL : ALL \ : severity auth.info \ : twist /bin/echo "You are not welcome to use %d from %h."