please help me to understand

[jono261970]

Hello,

I have an nt network and ms proxy 2 as our webserver\firewall. I often read about people advising that certain ports should be close. Can somebody please tell me how one would go about finding what ports are open and how to close them?

many thanks

jono

 

[browolf]

a program such as Active ports will show u what ports are open.

http://www.webattack.com/get/activeports.shtml

it might be easier tho to portscan your proxy's internet ip address from a different computer on the internet.
there are hundreds of such programs
e.g.

http://www.webattack.com/get/netview.shtml

depends on what ports are open depends on how to close them.
for instance you should not have wins or netbios bound to the internet side of your proxy.

for firewalls usually. it's best to close everything and then open them up as you need them ===============
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[jono261970]

Hi,

Thanks for your reply. I am beginning to have a better understanding since playing with the port scanner. I have scanned the ports on my router and apparently only ports 80 and 2468 are open. However ther are quite a few ports open on my 5 workstations.

how do I close the ports on a win 2k workstation?
is a port a virtual thing?
if ports 80 and 2468 are the only open ports on my router how come data can get to the ports on my other computers. Maybe these are local ports between computers on my lan?

Also, if ports 80 and 2468 are the only ports open on the router how does email get through on 25 and 110?

many thanks for your help

jono

 

[browolf]

i dont really know much(anything) about routers.

on win2k pro afaik it's possible to close everything except port 445 and port 135 (or was it 137)

you can get even more insight with a packet sniffer. i use ethereal on out network.

http://www.ethereal.com/

u got to install winpcap first

http://winpcap.polito.it/

which allows your computer to pick up packets.

try security forums specific info, there's lots of clever ppl there ;-)
===============
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