Blocking a Range of IP Addresses

Blocking a Range of IP Addresses

Blocking a range of IP addresses

Mar 19, 2019

You can choose to block a range of IP addresses as well as blocking individual IP addresses. While blocking a range can save time when you wish to block a network associated with a high-risk country or organization, you should be cautious about adding ranges with CIDR notation as there is a greater potential for blocking legitimate buyers if you make a mistake.

You can enter the process of blocking IP addresses from the individual order review pages or from the IP Blocking page accessible within Risk Tools. The IP Block list is limited to a maximum of 150 entries that may consist of either single IP addresses or ranges of IP addresses. You may add up to 25 entries at once.

Block a range of IP addresses from the IP Blocking page

  1. Sign in to your My Services page.
  2. Click the Store link.
  3. Go to Risk Tools.
  4. Go to IP Blocking.
  5. In the IP Addresses field, enter an IP address within the range that you wish block then click the Lookup IP button.
    Tip: You can typically get the netrange or CIDR notation for a network/organization using reverse DNS information.
  6. Click the See complete WHOIS info link.
  7. In the pop-up window, look for entries for NetRange and CIDR for the IP address for which you performed a look up.
  8. NetRange - for example blocks all IP addresses between and The hyphen to indicate a range can only appear within the last octet (number) of the IP address. Use this method when you have a very specific range of IP addresses you wish to block.
  9. CIDR - for example blocks all 256 IP addresses between and Use this method when you have a much larger range of IP addresses you wish to block such as countries or organizations.
  1. Enter the range of IP addresses that you wish to add in a valid format to the IP Addresses field.
  2. If you wish to block further orders from all IP addresses within the range, click the Add button. (The IP address range now appears in the IP Block List).
  3. On the top-right or bottom-right, click the Done button.

You can also enter up to 25 IP addresses (or ranges) to be added at one time, however you can only lookup information on a single IP address at one time. We strongly recommend reviewing reverse DNS lookup information along with the order information for possible signs of fraud for each IP address (or range) you wish to add so you do not inadvertently block legitimate buyers. You will only be able to tell if legitimate buyers are blocked if they contact you after seeing the checkout not available error page. You can then decide whether to remove the IP address from the IP Block List or process the order manually.

Block settings should be applied within several minutes of an IP address being added to or removed from a block list. In rare circumstances, it may be several hours before new block list settings take effect.

Note: Yahoo Small Business provides the IP address blocking feature as is and without warranty of any kind to Merchant Solutions and Store merchants to be used at the merchants' discretion. Merchants should carefully review the Reverse DNS Lookup information provided before blocking any IP address, as IP addresses may be dynamically assigned to users by certain Internet Service Providers possibly blocking legitimate buyers and not ensuring the fraudster is blocked from ordering. Also, as IP addresses may be falsified, merchants are advised to use AVS and CVV responses to determine which orders to approve, reject, or follow up with the issuing bank.