Advantages
- Users that are annoying you with attacks are blocked
- Users can't try and re-register with your site
- Helps secure your site
- You have control over who sees your site
Disadvantages
- Sometimes your blocking rules will infringe upon a valid surfer
- Blocking one IP is not always full-proof
Could they not get round this by turning their router on and off and getting a new ip. What about if they are using a modem this changes all the time.
Turning your router off then on will not get you a new IP address. Most broadband companies give a specific IP to the broadband router with a specific MAC address. This offers them more control and accountability for illegal activity. Using a modem is done in a similar fashion. Typically, modem users will get an IP of the same basic type: 293.184.28.* which is based upon the server they dial in to. It is possible, if using a modem, to get around an IP block; however, it's less likely a modem user will cause issues because they have such a slow connection and can't do as much as fast.
If they are using a computer in an internet cafe then if you block the ip address then you are blocking the whole cafe off from your site.
Well, I'm not 100% sure how ICs work; however, I would guess they have a few IP addresses. Those are split internally and given a multitude of IP addresses per each router. By blocking one IP, you're not blocking all computers. More likely you're blocking a block of computers. From what I can tell, hacking attempts come from home computers as ICs don't offer the anonymity a home offers you.
Typically when you block an IP, you'd want to block a range of IPs because the user can just get a new IP one number up or down in the list. So a typical block would restrict a set of IPs. You need to be careful when blocking; however, it does serve a purpose and should be used when necessary.
