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What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone
(6 answers)
Closed 10 months ago.
Im trying to make a phone number extension field but Im not sure what the maximum amount of digits it can have and I dont see any sources online.
I was asking the same question myself but I couldn't find anything conclusive. I did, however, find a couple of useful bits of information that helped me come to a decision.
Robert Pepper at GetVoIP, says:
In an older PBX, that would be four digits, and limited to the same building. In a hosted PBX, it can be three, four or five digits, and the extension can be anywhere in the world, including your cell phone.
But, GoToConnect's website states:
An extension is a three to six-digit number identifying a specific call path configuration that allows you to dial and connect to another caller internally.
With that in mind, I decided to use six digits as a max length, until I learn otherwise.
Generally E.164 formatting using on apps.On this format max length is 15 this but using '+' for countrycode.
if you use Instead of '+' '00' it will be max 16 .
Related
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What is the optimal length for user password salt? [closed]
(5 answers)
Closed 4 years ago.
Why is the salt not more than 8 ~ 16 characters long?
Also, why in most cases is it in the front or end of the password, and not in different positions?
Is this to make it harder for the breaker? Or is it useless?
Because more salt doesn't serve a useful purpose.
The point of salt is to prevent some parallel attacks from working in a reasonable amount of time/memory, and/or drive space. (You can no longer have a table that says Hash A => Password A, because even if you had enough disk space to construct a rainbow table, the salt makes the number of possible entries way beyond feasibility. And you can no longer hash a potential password once and compare it against a bunch of hashes at a time, because the salt is quite likely to be different for each hash.)
16 characters gives you somewhere between 10^16 and 96^16 times as many possibilities, which already fits the definition of "way beyond feasibility". Past a certain point, you're simply increasing your own storage requirements for no significant benefit.
The salt of 8 characters is enough against any imaginable in real life dictionary attack, it makes any dictionary or rainbow table useless.
This question already has an answer here:
Storing 'long' type in firebase
(1 answer)
Closed 5 years ago.
Adding a big number in Firebase Dashboard is always rounding it to an even number.
For example adding this 10156050407559741, it changes to 10156050407559740 or 10154224540777163 to 10154224540777164.
Basing from #MichaelLehenbauer's answer here:
Integers between 2^52 and 2^64 may lose precision (get rounded to the nearest integer representable by a 64-bit float).
And from the options on the same post, it would be best to store the numbers as Strings instead (still depending on your use-case though):
Store the numbers as strings. As you suggested, you can just store the number as a string. But this can be inconvenient and does limit the validation you can do in the security rules.
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What is the maximum length of a URL in different browsers?
(18 answers)
Closed 7 years ago.
In the past, I learned that the amount of data that can be sent through the HTTP GET method is limited and this is due to the limitation of the number of the characters in the URL, because an URL can not contain more than 255 characters.
But recently I noticed an URL that contains 294 characters where the query part (the string after the ?) contains 269 characters.
So, is there really a limit in the data sent through GET ? or am I outdated ?
Yes, there is a limit, and you can increase it. This is because data sent through the get method is passed through the url of the browser.
However different browsers may have different limits, and HTTP servers will also have different limits.
reference
This question already has answers here:
What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone
(6 answers)
What is the minimum length of a valid international phone number?
(3 answers)
Closed 10 months ago.
What is the max and min digits for an international telephone number?
(country code + area code + phone number)
, where the format of telephone
numbers is standardized by ITU-T in
the recommendation E.164, which
specifies that the entire number
should be 15 digits or shorter,
Source: http://en.wikipedia.org/wiki/Telephone_number
Also, check this other question on SO:
What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phone
Telephone numbers are standardised by ITU-T in their recommendation E.164. In the recommendation they say telephone numbers should not exceed 15 digits.
So it's up to the telephone operators and local standards.
Most operators don't allow you to send SMS messages to numbers which are more than 16 digits long. So you'll be safe with 16 digit limit.
Edit A nice summary of misconceptions about phonenumbers can be read at https://github.com/googlei18n/libphonenumber/blob/master/FALSEHOODS.md
The answer to that question can (and does) change in a fashion which is entirely too fluid to be able to provide you with a definitive answer. Carriers or countries can change their numbering plans (adding area codes or adding digits or the like) at any time.
A website which I often use as a reference for International Phone Numbers is http://www.numberingplans.com/
I believe they also sell their databases, if you are wanting to validate individual numbers within your own system..
15 digits is maximum, refer this link
https://en.wikipedia.org/wiki/E.164
Although the standard is talking about 15 digits maximum, a call number extension using Direct Inward Dial (DID) and Private Branch Exchange (PBX) technologies is oftenly used in order to call a specific person or department inside an organisation, which can make a phone number longer than 15 digits (note "-1234" suffix at the end):
0049 (30) 123456789-1234
In our systems we use the limit of 20 digits.
Actually, the question asks for an "international" phone number but mentions an area code which some nations don't have. In E.164 the national part was found be no more than 12 digits at the time of writing. Then they added a country code and atleast a "+" for the prefix.
Longer subscriber numbers may be possible however and we know that they do get assigned in some regions of the world. The technical limitation for that can be found in the 3GPP standards (like GSM) and ISDN standards (like DSS1) which have 10 bcd-encoded bytes for the subscriber number - plus a byte for the prefix which can be up to 4 digits to be dialled. That adds up to a limit of 24 digits for a viable subscriber number.
Is there a maximum lengh for a file extension? The longest one I've seen is .compiled (8 chars)
Useless Background
I'm creating a IHttpHandler to return image icons for a specific filename. I'm simply calling a FileImage.axd?ext=pptx. I'm generating the files on the fly using SHGetFileInfo similar to my post for WPF, then caching them locally in a folder with the filename 'pptx.png'. I'd like to validate the length and trim it to prevent a DoS type attack where someone would try to generate images for and infinite number of junk characters (eg FileImage.axd?ext=asdfasdfweqrsadfasdfwqe...).
As far as I know, there is no limit, except the maximum length of the file name. Extension is not treated specially except in FAT16.
I agree with Arkadiy - there is no formal limit now that the DOS 8.3 system is a thing of the past (or other similar, limited systems). I would say that the majority of the extensions I've seen are in the range 1-3; Java uses 4 for .java and 5 for .class. Your example with 8 is longer than I recall. If I were scoping, I'd aim for 'unlimited'; if that's not feasible, allow at least 16 characters - with the confident expectation that in fact 16 would be quite sufficient for current systems.