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A Bad IP Address

Of course, if I said someone lived in a ‘bad neighborhood’ or was rejected for a loan due to a bad credit score then you’d all know what I mean.  But in this ever increasing online world there’s another aspect to your existence that can have an affect on your life – and that is your IP address.

Your IP address is of course your unique identifier assigned to your computer when it’s online.  It’s full name is internet protocol address and you can read the technical background on the wonder of IP and it’s role in TCP/IP here.  But suffice it to say, that without this address it is impossible to communicate online, it allows you to visit websites, download films and DVDs and send emails and just about every thing else available on the web.

In fact your IP address will already partly affect some areas of your online experience.  Have you ever been blocked from a site or video? Perhaps tried to watch something on YouTube  and been told it’s not available in your country?  Well that’s all down to the location of your IP address – mainly what country it originates from.

Your IP Address

 So if you do a quick search online, many sites will tell you that to find your IP address – just select command prompt type in the command ipconfig /all as I’ve done in the screen shot above.  From this screen you might suppose that my IP address is 192.168.1.15 as circled.  This is actually a private IP address and is only valid in my internal network – it’s not my real internet facing address.   Within my house like millions of other people I have multiple devices like laptops, phones and PCs all connected through my internet connection, these internal addresses allow them to communicate through my single real IP address.

To find your real IP address, you need to look at the configuration screen of your modem or router, the device that actually connects through to your internet provider.

Here’s mine –

Real IP Address

Well a bit of mine, obscured for privacy reasons !  This address is allocated by my ISP to my connection and all my devices will appear to the internet to be from this single IP address. So my son, downloading games to his Xbox will appear at the same address as my wife and I surfing from the same location – we all originate from the same single address.

About Bad IP Addresses

So although at any point in time, your connection will be the only one online using this particular IP address – it doesn’t mean you always have.  If you can see from the screen shot – the address has been assigned dynamically from my ISP – who basically have a big pool of addresses which they allocate individually to their customers.  All the addresses will be assigned from this database which are registered to specific providers and countries.  This is how geo-targeting works – everyone knows which country an IP address is assigned to.  Which is why you’ll need a US IP address for Hulu and a UK address for BBC Iplayer, anyone can look up which country and IP address is located in very easily.

ip-address-bad

Sometimes an IP address can be used to send out millions of spam messages, attack websites or download and share pirated software and films.   Most hackers and spammers will normally try and use someone else’s address to hide their location – obtained via viruses and malware without the owners knowledge.

This is the sort of behavior that can find any IP address blacklisted – on some of the thousands of lists of ‘bad IP addresses’.  Many of these lists have been developed to combat Spam and so mail servers across the world can block any mail received from them.  Unfortunately IP addresses are routinely shared and reallocated to you can easily end up with one these being issued to your connection.

Common scenarios of being allocated a ‘bad IP address’:

Problems Buying Things Online 

Ever tried to buy something online and found your payment couldn’t be processed?  You might get some generic error message from the retailer saying it couldn’t accept payment or something similar.  This may be that your IP address has found itself onto a blacklist somewhere.  Frequently IP addresses are blocked if they’ve been used by online criminals perhaps with stolen credit card details or similar.  Some of the spam lists are also used by big payment processors – some companies block addresses from whole countries, certainly a problem if you’re accessing the internet from somewhere like Nigeria.

Difficulty with Sending Email

If your address (or worst your mail server address) has been put on an internet blacklist you may find problems with emails.  Maybe emails bouncing back undelivered often with obscure sounding error messages.  Many of the big webmail providers like Hotmail and Yahoo will routinely block emails from IP addresses on the blacklists.

Accessing Websites and Forums

Internet blacklists are often used by many sites to try and prevent spammers and hackers accessing the sites. Many websites will automatically block access from IP addresses which try and login to secure servers for example. Here’s the message I get whenever someone tries to hack into one of my websites.

IP:       202.102.253.6 (CN/China/-)
Failures: 5 (sshd)
Interval: 300 seconds
Blocked:  Permanent Block

Log entries:

Sep 13 04:51:36 xenon sshd[23175]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.102.253.6  user=root
Sep 13 04:51:38 xenon sshd[23175]: Failed password for root from 202.102.253.6 port 6291 ssh2
Sep 13 04:51:41 xenon sshd[23179]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.102.253.6  user=root
Sep 13 04:51:43 xenon sshd[23179]: Failed password for root from 202.102.253.6 port 4974 ssh2
Sep 13 04:51:46 xenon sshd[23185]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=202.102.253.6  user=root

You can see that after three failed logins, the system will now block any attempted access from that specific IP address. It wouldn’t matter if that IP address was assigned to a different person or location, until that restriction is removed you wouldn’t be able to view my website using that address.

There are further questions 0f course – how do I find out if my address is blacklisted? How can I change my IP address?  Which I will try and address in my next post –