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APPJAIL-DNS(8) System Manager's Manual APPJAIL-DNS(8) NAME appjail-dns -- DNS information for AppJail users SYNOPSIS appjail-dns [files ...] DESCRIPTION The appjail-dns utility is a command to generate a hosts(5)-like file to be used by scripts and services, such as a DNS server. appjail-dns can read one or more hosts(5)-like files by removing any com- ments. After reading and displaying all the specified files, appjail-dns will generate a list of DNS hostnames for each jail in each virtual net- work. The syntax of each line is exactly as specified in hosts(5)-like, but the jail's hostname follows a particular syntax: "<Jail Name>.<Virtual Network>HOST_DOMAIN" . The virtual network host name syntax is "<Virtual Network>HOST_DOMAIN" . See appjail.conf(5) for a description of the HOST_DOMAIN parameter, but as you can see, it is used exactly as is, assum- ing it is prefixed with a dot. This document also explains how to use the rc(8) script to implement appjail-dns with a DNS server, in this case DNSMasq. The rc(8) script checks the current hosts(5)-like (appjail_dns_hosts: /var/tmp/appjail-hosts) file against the output of appjail-dns at intervals (appjail_dns_interval: 60) using a checksum; if it detects a change it will write the new content to the hosts(5)-like file and execute the hook (appjail_dns_hook: /usr/local/share/appjail/scripts/dnsmasq-hook.sh) only if it has the execution bit set. A hook is simply an external program that has two responsibilities: filter- ing the hosts(5)-like file and restarting the DNS server. These responsi- bilities depend entirely on the DNS server, as it may not need to be restarted, or even the hook may not need to modify the hosts(5)-like file for the DNS server to interpret it correctly. For example, if we use the following file for DNSMasq: /usr/local/share/appjail/files/dnsmasq.conf : addn-hosts=/var/tmp/appjail-hosts no-resolv server=208.67.222.222 server=208.67.220.220 With the necessary parameters in our rc.conf(5): dnsmasq_enable="YES" dnsmasq_conf="/usr/local/share/appjail/files/dnsmasq.conf" We are configuring DNSMasq to use /var/tmp/appjail-hosts as our hosts(5). Since it can perfectly interpret a hosts(5) file, it is not necessary to modify it. The hosts(5)-like file is passed to the hook as the first argument, but we don't need it, since the only thing our hook needs to do is restart DNS- Masq. /usr/local/share/appjail/scripts/dnsmasq-hook.sh : #!/bin/sh service dnsmasq reload AppJail uses the above hook in its rc(8) script, but you can change to any other hook by changing the value of the appjail_dns_hook parameter in your rc.conf(5): appjail_dns_enable="YES" appjail_dns_hook="/usr/local/share/appjail/scripts/dnsmasq-hook.sh" Once everything is done, we can start the rc(8) scripts: # touch /var/tmp/appjail-dns # service dnsmasq start # service appjail-dns start Since every time the rc(8) script is restarted, it checks if there are any changes between the output of appjail-dns and the current hosts(5)-like file, we should have the file with content, assuming that there are already jails created and that are in an existing virtual network. # cat /var/tmp/appjail-dns 10.0.0.1 ajnet.appjail 10.0.0.2 filebrowser filebrowser.ajnet.appjail 10.0.0.3 jtest jtest.ajnet.appjail In my case, I have enabled SHORTEN_DOMAIN_NAMES, so a shorter domain name is available in that file, as you can see. EXIT STATUS The appjail-dns utility exits 0 on success, and >0 if an error occurs. SEE ALSO appjail-network(1) hosts(5) appjail-tutorial(7) AUTHORS JesAos Daniel Colmenares Oviedo <DtxdF@disroot.org> FreeBSD ports 15.quarterly March 30, 2024 APPJAIL-DNS(8)
NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | SEE ALSO | AUTHORS
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