net.dns

Get and check your DNS records.
To resolve your domain name, IANA controlled nameservers are used. In case of political intervention, a fail-over to ORSN is implemented, but currently not in use. You'll find a notice in this section when a fallback occurs ;)

Transaction ID / Source Port randomness

2008-07-08 See Dan Kaminsky's Website to check if your nameservers are vulnerable to this "recent" design flaw.
Clez.net won't provide a specific check for this issue for some time - I'm migrating the systems this month and don't want to add extra complexity like an autoritative master nameserver, catching your request (technically similar to the TCP information in web.agent) and analyzing source ports and transaction tokens. But the version information in the #overview tab can give you some clue. As you probably know, BIND 8 will stay unpatched for some time, so answering to chaos:version.bind requests with an unpatched version number (< 9.5.0 | < 9.4.2 | < 9.3.5) will now be reported as an error.

Service resource records

2008-07-14 This check now includes probes for the most common SRV records, like _jabber._tcp, _xmpp-server._tcp, _sip._udp and _ldap._tcp. Additionally, presence of _http._tcp, _smtp._tcp and _jabber (without the ._tcp pseudo-subdomain) will throw a warning. SRV relations have an orange color in the graph.