Network Solutions worldnic.com nameservers both appear down. Pings get through occasionally, this may be an indication that they are being DOSed. I used to think that their DNS hosting services would be stable since they were “the” original registrar. But this is the second time in a few months that they’ve been down for a sustained period.
I just switched DNS nameservers so I no longer have to deal with them. Now when the domain comes up for renewal (not this one, by the way) I will use GoDaddy instead. They seem to be really great, and any dns changes (including nameserver changes) propagate really fast.