Por falar de qualidade, os vossos DNS's não estão correctamente configurados. O vosso DNS está OPEN e aponta para:
ns2.lusawebtronica.com. [126.96.36.199] [TTL=86400]
ns1.lusawebtronica.com. [188.8.131.52] [TTL=86400]
Fica aqui um extrato do que pode acontecer a quem não liga aos serviços de DNS e os deixa neste estado:
OK, for the non-techies out there, here is what might happen when you let everyone use your DNS server as a resolver.
For example, I'm a spammer. I create a hostname for spam, something.myspam.tld.
After that, I query your DNS server to resolve the host something.myspam.tld. It resolves that host and stores the info in its cache. All further requests for that host do not result in propagated lookups but are answered by the server from its cache, until the exipration for the zone occurs.
After that, I set your DNS server as the authoritative server for my zone with the domain registrar.
After that, I start sending spam.
Now, you are screwed because it looks as if your DNS server is being used for spam.
There is nothing new about this. It's been like that for years.