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This just came into my mind when I was at work last week allocating an IP addresses to some of our servers when I noticed that our pool of IPs are near depletion. I wonder what happens when the pool of available 16-digit credit card numbers gets depleted and reaches to zero? Can they recycle used/disconnected card numbers?
@Angko wrote:This just came into my mind when I was at work last week allocating an IP addresses to some of our servers when I noticed that our pool of IPs are near depletion. I wonder what happens when the pool of available 16-digit credit card numbers gets depleted and reaches to zero? Can they recycle used/disconnected card numbers?
Yes.
Also there's a metric ton more credit card numbers (16^10) vs the 4 billion addresses in IPv4; and it's nowhere close to the rate of use either I suspect.
Speaking as someone who once did backbone engineering, I'm not worried about CC number exhaustion .
@Angko wrote:This just came into my mind when I was at work last week allocating an IP addresses to some of our servers when I noticed that our pool of IPs are near depletion. I wonder what happens when the pool of available 16-digit credit card numbers gets depleted and reaches to zero? Can they recycle used/disconnected card numbers?
Sure. They recycle CC#s. Some banks also recycle old checking account numbers. My Amex CC#, closed in the 80's, was recycled.
@Revelate wrote:
@Angko wrote:This just came into my mind when I was at work last week allocating an IP addresses to some of our servers when I noticed that our pool of IPs are near depletion. I wonder what happens when the pool of available 16-digit credit card numbers gets depleted and reaches to zero? Can they recycle used/disconnected card numbers?
Yes.
Also there's a metric ton more credit card numbers (16^10) vs the 4 billion addresses in IPv4; and it's nowhere close to the rate of use either I suspect.
Speaking as someone who once did backbone engineering, I'm not worried about CC number exhaustion .
You meant 10^16 I'm sure. Like IPs, the leading digits of credit cards are assigned in clusters to banks and there is also a check digit which cuts the numbers a bit. Still, there are plenty CC numbers to be had.
That's nice info! I didn't know that they can recycle used numbers. All the while I thought eventually there will be an IPv6-version of credit card numbers.
@cashnocredit wrote:
@Angko wrote:This just came into my mind when I was at work last week allocating an IP addresses to some of our servers when I noticed that our pool of IPs are near depletion. I wonder what happens when the pool of available 16-digit credit card numbers gets depleted and reaches to zero? Can they recycle used/disconnected card numbers?
Sure. They recycle CC#s. Some banks also recycle old checking account numbers. My Amex CC#, closed in the 80's, was recycled.
+1. They are not unique numbers and I know that, at least in the past, numbers could be re-issued as soon as 6 months from date of cancellation of the number to a previous cardholder. Those of us who have been around a while remember those little "magazines" that retailers used to have of stolen credit card numbers, they would have to look them up to see if they were stolen. I'm sure the card issuers have automated the process. However, since they are NOT unique numbers, law enforcement cannot enter the credit card numbers in their state or national crime information databases (Yes, NCIS is wrong about that!)
Interesting topic. Well AMEX has 15 numbers and the others have 16. Perhaps they either:
a)add a letter at the end to indicate which network it is (e.g, M-Master Card, V-Visa, D-Discover)
b)expand the amont to 17 or 18
Just ideas...
@allthebest wrote:
FYI first number of a credit card indicates what type it is. 3-Amex, 4-visa, 5-master, 6-discover.
And adding to the list:
Starts with 34 and is a 15-digit number - Amex
Starts with 37 and is a 15-digit number - Amex
Starts with 3 and is a 14-digit number - Diners
Starts with 3 and is a 16-digit number - JCB
Starts with 2131 or 1800 - JCB
Start with 6011 - Discover
So... if we can determine the card network based on the prefix of the card number, why do majority of the shopping carts has pull down selection menu where you select the network for the credit card numbers you just entered? Hahaha!
@Angko wrote:
@allthebest wrote:
FYI first number of a credit card indicates what type it is. 3-Amex, 4-visa, 5-master, 6-discover.And adding to the list:
Starts with 34 and is a 15-digit number - Amex
Starts with 37 and is a 15-digit number - Amex
Starts with 3 and is a 14-digit number - Diners
Starts with 3 and is a 16-digit number - JCB
Starts with 2131 or 1800 - JCB
Start with 6011 - Discover
So... if we can determine the card network based on the prefix of the card number, why do majority of the shopping carts has pull down selection menu where you select the network for the credit card numbers you just entered? Hahaha!
@Anonymous @ Diner's...if I remember correctly, didn't those 14 digit numbers transition to 16 and are treated as MasterCards?
Diners Club is so '80s.