On 8/27/06, Joachim Schipper <j.schipper@math.uu.nl> wrote:
> Actually, you got it the wrong way round - nmap assumes a port is
> filtered when it gets no response.
You're correct, an oversight on my part.

From the nmap man page (which I clearly failed to read):
'Filtered means that a firewall, filter, or other network obstacle is
blocking the port so that Nmap cannot tell whether it is open or
closed.'

Perhaps Greg's suggestion has merit as well -- his ISP may be silently
dropping services destined to those ports. Mine drops tcp/25 and
tcp/80 that I'm aware of.