Revealing Port numbers and IP addresses

[Howard Kaikow]

Is it a security issue if one reveals theport numbers and IP addresses for a system?

I ask because Kaspersky has a tool called GetSystemInfo that lists a bunch of info about a system.

The list includes Opened TCP/UDP ports and associated IP addresses.

Should this info be made available to others?

[dmphotography]

Yes is the simple answer.

If you're talking about publicizing your IP and open port information, it's like giving a burglar the keys to your house and saying "Here ya go".
You might as well give him your work schedule as well so he know's when to rob you.

As far as displaying visitor's to your server's information, why would you?

If I saw you posting my IP after visiting your site, I wouldn't ever go back because I first would want to know why you want that information and secondly, you COULD pose a risk to me by having that made public.

You're only going to see the users have standard ports such as 80 open that visit you and if they have a good firewall, it's no serious threat to them. Many ISP's have dynamic IP's and I recently discovered AT&T even rotates IP's every 8 hours to ensure better safety for their DSL users since so many people don't understand the value of good firewalls.

Bottom line, it's bad practice and in some cases can even be illegal to store IP's and user information for more than a small given period.

[Izzy]

Is it a security issue if one reveals theport numbers and IP addresses for a system?

Not if you mean the local LAN IP numbers as those outside your network ie. on the WAN Internet can't access those IPs anyway.

Correctly configured firewalls do a good job of protection and should be used by all.

I ask because Kaspersky has a tool called GetSystemInfo that lists a bunch of info about a system.

The list includes Opened TCP/UDP ports and associated IP addresses.

Should this info be made available to others?

Not unless you want to give it to them and once again if it is local IP addresses then they are useless to anyone from outside your network.

As a test try and access a local IP from the Internet by asking a close friend perhaps or using:
http://hexillion.com/co/DomainDossier.aspx

Here's a couple of sites with security info:
http://www.diamondcs.com.au/
http://www.grc.com/default.htm

Internet IPs, your ISP provided IP, is public knowledge and these Internet IPs are used to locate all domain names on the Internet.

If I saw you posting my IP after visiting your site, I wouldn't ever go back because I first would want to know why you want that information and secondly, you COULD pose a risk to me by having that made public.

This information is readily available to a server when you access it from the Internet using just these few server variables:
ipaddr = REMOTE_ADDR, browser = HTTP_USER_AGENT, referrer = HTTP_REFERER etc.
and the information gleaned can easily be included in a HTML file for viewing when you access a web page.

Those are also used in the Apache access log file so they are known to just about anyone who wants to know, but as always, firewalls will help keep out the burglars.

This method is used by many including those Who Am I and WhatisMyIP kind of web sites and is used by just about every PayPal type payment gateway site, so they know where you are coming from, they also link that info to your credit card details for fraud prevention - which fails if you use a VPN or an anon proxy.

Many ISP's have dynamic IP's and I recently discovered AT&T even rotates IP's every 8 hours to ensure better safety for their DSL users since so many people don't understand the value of good firewalls.

Oh If only that were true, as the real reason for this IP change is to help prevent or rather make it very difficult to have an unauthorized web server and or file sharing server (torrents comes to mind here) on your Cable, DSL or ADSL style Internet connection.

...in some cases can even be illegal to store IP's and user information for more than a small given period.

This is also incorrect, as you should know the Internet is a lawless place and as yet there are no laws that prevent you either from obtaining an IP related to a domain name nor is there a law that prevents you from keeping another's IP or any of the demographics you collect from visitors for as long as you see fit.
See http://centralops.net/ and find all the info you want about just about anyone on the Internet - not illegal by the way.

Ask Google about this or any other web site that collects and stores your information, with or without your permission, or indeed without you even knowing they are collecting it.