I'm only on a Link2, but on idle used to always use around 110 (in regards to the numothersock).
I requested from VPSLink that the limit be raised, however was notified I needed a Link3 account to reallocate resources. Since my VPS runs at around 50% utilization of memory, there isn't an immediate need to upgrade. It sounds like you are on a Link3, so maybe a support ticket would allow an official VPSLink person to upgrade your resources, I don't know.
I hunted the problem down to postfix, which I do like indeed, but it appears to hog sockets. Throwing out unneeded processes would shave about 20 used sockets, however I hate the idea of crippling postfix.
Eventually I needed to simply switch to exim4. Now I usually run at about 25 numothersock.
Are you using postfix?
Another tip for people to check what is hogging their sockets is lsof:
lsof -U
I look forward to hearing other responses
