The largest telco in Latin America. Over 16.5M lines. And they can't configure their freaking DNS correctly.
[ralsina@monty ~]$ host -t any telmex.com.ar telmex.com.ar has SOA record ns2.telmex.com.ar. root.telmex.com.ar. 3 36000 3600 3600000 36000 telmex.com.ar name server ns2.telmex.com.ar. telmex.com.ar name server ns3.telmex.com.ar. [ralsina@monty ~]$ host ns2.telmex.com.ar. Host ns2.telmex.com.ar not found: 3(NXDOMAIN) [ralsina@monty ~]$ host ns3.telmex.com.ar. Host ns3.telmex.com.ar not found: 3(NXDOMAIN)
Before you ask, yes, their domain is really telmex.com, but they did register telmex.com.ar and have a lame web redirector at www.telmex.com.ar.
IN fact, according to www.nic.ar, that should be ns2.telmex.net and ns3.telmex.net so it's plain and lame misconfiguration (BTW: what happened to ns1?).
People of Telmex, you can hire me to fix it for you. I won't overcharge you. I will however, snicker a little.