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Which Ports Need to be Open?

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by pozotech 1 view

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I have a W2k Server Machine running Proxy 2.0, also have another W2k machine that is hosting a website. I have a list of all the different ports - what I would like is a list of the ports that need to be open on each of these machines. The proxy server is dual honed with a nic for the internal and ext. network. Currently all ports are open on the ext. nic on both machine and I know this is a security problem. Thanks Jeff

6 replies

by lordinfidel

This will depend on what you want to allow in.

If all you want is web traffic then allow tcp port 80.

If you want e-mail then port 25. ssl -443, FTP - then 21 Etc. This RFC covers most of the ports:

http://www.faqs.org/rfcs/rfc1700.html
The rule to remember is to only allow what you need.

by lordinfidel

Some more info/advice....

Depending on your corporate culture, you may not want to allow everything out, and this is the reason why.

When you begin to allow unadulterated access out, that means more time you have to support the different apps that your users want to use (napster, gnutella, Mirc etc.)

Most of these apps are non-business related.
And can cost your company in wasted time which then calculates to $$$$.

From a security standpoint. Only ever allow what you need both in and out. Rememeber, what goes out must come back in. Paranoria
is basically the de facto standard. Assume that every hacker is trying to get into your network using every port open to them.

Which boils down to... Don't allow what you don't need to. It is harder to take away then it is to give.

Take the advice for what it's worth, your not obligated to follow it.

by highorbit

Following the above...

It depends on what you want people to access. As an example we have all ports except FTP, HTTP, Telnet, SMTP and a few others blocked for incoming traffic but everything is open to outgoing.

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