I have a Thompson TG585v7 router/firewall whose firewall is configured to
FORWARD several ports to a computer
X54 within the LAN.
These ports are in the range
1024 through to 2500
X54 computer is now gone and so there is nothing "listening" on those final destination ports
If I use scan the firewalls public IP using
nmap -A -p 1000-2500 219.xxx.xxx.xxx
$ sudo nmap -A -p 1000-2500 219.xxx.xxx.xxx Starting Nmap 6.40 ( http://nmap.org ) at 2015-02-21 13:14 NZDT Nmap scan report for dsldevice.lan (219.xxx.xxx.xxx) Host is up (0.011s latency). Not shown: 1500 filtered ports PORT STATE SERVICE VERSION 1723/tcp open pptp THOMSON (Firmware: 1) Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port Device type: broadband router Running: Thomson embedded OS CPE: cpe:/h:thomson:st_585 cpe:/h:thomson:st_536i OS details: Thomson ST 585 or ST 536i ADSL modem Network Distance: 1 hop Service Info: Host: SpeedTouch
It reports other fully functioning - in this case
1723 - ports that are open and have a service listening, but doesn't show these ports that are forwarded to a non-existant machine.
So My question is, if
nmap reports that a port is "open", does it mean that both the following is true?
- the firewall is accepting connections on the given port
- there is a machine/service listening on the other end