20.2. Internet super daemon (xinetd)

IPv6 is supported since xinetd version around 1.8.9. Always use newest available version. At least version 2.3.3 must be used, older versions can contain remote exploitable security holes.

Some Linux distribution contain an extra package for the IPv6 enabled xinetd, some others start the IPv6-enabled xinetd if following variable is set: NETWORKING_IPV6="yes", mostly done by /etc/sysconfig/network (only valid for Red Hat like distributions).

If you enable a built-in service like e.g. daytime by modifying the configuration file in /etc/xinetd.d/daytime like

# diff -u /etc/xinetd.d/daytime.orig /etc/xinetd.d/daytime 
--- /etc/xinetd.d/daytime.orig Sun Dec 16 19:00:14 2001 
+++ /etc/xinetd.d/daytime Sun Dec 16 19:00:22 2001 
@@ -10,5 +10,5 @@ 
        protocol = tcp 
        user = root 
        wait = no 
-       disable = yes 
+       disable = no 
 }

After restarting the xinetd you should get a positive result like:

# netstat -lnptu -A inet6 |grep "xinetd*" 
tcp 0 0 ::ffff:192.168.1.1:993  :::*  LISTEN  12345/xinetd-ipv6 
tcp 0 0 :::13                   :::*  LISTEN  12345/xinetd-ipv6 <- service
╛ daytime/tcp
tcp 0 0 ::ffff:192.168.1.1:143  :::*  LISTEN  12345/xinetd-ipv6

Shown example also displays an IMAP and IMAP-SSL IPv4-only listening xinetd.

Note: An IPv4-only xinetd won't start on an IPv6-enabled node and also the IPv6-enabled won't start on an IPv4-only node (will be hopefully fixed in the future).