Ok. This covers every ipv6 and ipv4 address.
“^\s*((([0-9A-Fa-f]1,4}:){7}([0-9A-Fa-f]{1,4}:)6}(:[0-9A-Fa-f]{1,4})|:))|(([0-9A-Fa-f]1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2}))|:))|(([0-9A-Fa-f]1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3}))?:((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9]))3})):)3}(((:[0-9A-Fa-f]{1,4}){1,4}))0,2}:((25[0-5]))|:))|(([0-9A-Fa-f]1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5}))0,3}:((25[0-5]))|:))|(([0-9A-Fa-f]1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6}))0,4}:((25[0-5]))|:))|(:(((:[0-9A-Fa-f]1,4}){1,7}))0,5}:((25[0-5]))|:)))(%.+)?\s*$”
Lord have mercy
Please don’t. Use regex to find something that looks like an IP then build a real parser. This is madness, its’s extremely hard to read and a mistake is almost impossible to spot. Not to mention that it’s slow.
Just parse [0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3} using regex (for v4) and then have some code check that all the octets are valid (and store the IP as a u32).
And dupe check. 0.0.0.0 and 000.000.000.000 may both be valid, but they resolve the same
Fuck that, if for whatever reason I’m writing an IP validator by hand I’m disallowing leading zeros. Parsers are very inconsistent, some will parse 010 as 10, others as 0o10 == 8 (you can try that right now with a POSIX
ping). Talk about a footgun.some will parse 010 as 10, others as 0o10 == 8
…and that’s me in the fetal position, thanks.
Definitely, tho if you store it as a u32 that is fixed magically. Because 1.2.3.4 and 1.02.003.04 both map to the same number.
What I mean by storing it as a u32 is to convert it to a number, similar to how the IP gets sent over the wire, so for v4:
octet[3] | octet[2] << 8 | octet[1] << 16 | octet[0] << 24
or in more human terms:
(fourth octet) + (third octet * 256) + (second octet * 256^2) + (first octet * 256^3)True enough for database or dictionary storage, but a lot of times things get implemented in arrays where you still wind up with two copies of the same uint32.
Because 1.2.3.4 and 1.02.003.04 both map to the same number.
But 10.20.30.40 and 010.020.030.040 map to different numbers. It’s often best to reject IPv4 addresses with leading zeroes to avoid the decimal vs. octal ambiguity.
I don’t know why anyone would write their IPs in octal, but fair point
It’s not about how people write them, it’s how parsers parse them. IPv4 has been around since 1982, and most parsers interpret leading zeros as octal.
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Made that joke in an interview once.
They didn’t think it was funny. They truly thought Regex was the solution to, but never the cause of, all problems.
They wanted to make a Regex to verify every single address in the world. Dodged a bullet
Holy hell yeah you did. How would you go about doing that in a single expression? A bunch of back references to figure out the country? What if that’s not included? Oy.
You wouldn’t. It’s not possible. Which is what I told them.
And why would you want to? Legally if you change the given address, and it fails to get delivered - that is on you. Not them.
Some countries have addresses that are literally ‘Last house on the left by the Big Tree. Bumban(Neighborhood). NN (Country)’. Any US Centric validation would fail this but I assure you - mail gets delivered just fine.
The only valid regex is
(.+). Maybe add a separate country field (especially because some Americans wholeheartedly believe that the entire world should understand that “foobar, TX” means “foobar, Texas, United States”) (don’t get me started on states whose abbreviations are also ISO country codes).Unfortunately I guess business people only care about getting fewer support calls for missing shipping details, not correctness or a couple of calls from customers who live in the boonies. Then the proper answer is a form with a bunch of fields… which Americans will inevitably fuck up by making the “State” field mandatory despite most countries not having an equivalent.
What I’d really do is use one of those services that automatically fill on the address using google maps or whatever. Not perfect, probably not free, but a whole lot less work for presumably way fewer PEBCAKs from customers.
If you’re using one of those services then PLEASE allow manual entry / override because I’ve had forms like that which I were blocked from filing in because it didn’t acknowledge that my address existed.
/.+(road|street).+/ resigns
It’s always a treat to debug a regex of that size.
I knew there would be someone with the regex.
You’re more of a perl programmer than network engineer :P
.*
Technically, this one also matches everything:
*exits the room*
0.0.0.0/0 0::0/0
You didn’t specify it couldn’t be in CIDR block notation…
::/0
Remember, when we abbreviate an ipv6 address all leading zeros are reduced to a single 0.
E.g
0003 would just become 03
When there are geoups of 4 zeros these can be represented as a single 0 or as a double colon ::
But we can only use the :: once so when summarizing an address containing multiple groups of 4 0s one after the other they can all be abbreviated to a single ::
Eg
fe80:0000:0000:0000:0210:5aff:feaa:20a2 would become fe80::210:5aff:feaa:20a2
Therefore it is perfectly valid to abbreviate an address of 0000:0000:0000:0000:0000:0000:0000:0000 /0 to just ::/0
Eh, I’ve seen some software internally prefer 0::0 instead of just ::0 or :: . Notation wise though you are correct, it is unnecessary.
0.0.0.0 /0 ::/0
SUCK MY DICK, GRU!
Haha spot on
This is the way.
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Its CIDR notation. So /0 means the subnet mask has no on bits and would read as 0.0.0 0 if you had a /1 that turns 1 bit on in the subnet mask, so it would be 128.0.0.0.
If i had a /24 which is the subnet mask used for most small networks like your home router. There would be 255 minus 2 addresses available for clients (phones, pcs etc) so the subnet mask would have 24 on bits and read 255.255.255.0, which you may be familiar with.
(Assuming you dont know much, not to insult you, you might know plenty), but when writing any kind of instructions or guides, i was always told to assume the reader knows absolutely nothing and miss nothing out.
:00-:ffEdit: Just learnt this can be also noted as:
::-::fWhat about IPv4
0.0.0.0/0
Better hope the goon hasn’t heard of IPv6 either, or you’re toast
::/0
Undefined
This is gonna take a while…
0.0.0.0
0.0.0.1
0.0.0.2
0.0.0.3
…
0.0.0.0/0
::/0
Winrar
Chicken dinrar?
0.0.0.0/0
This reminds me of something I saw online maybe 20 years ago now. Someone created a torrent with a name like “every IP address ever (hacking tool)” and uploaded it to Suprnova, which ended up having thousands of people seeding it. It was just a text file with every IPv4 from 0.0.0.0 to 255.255.255.255 😂
Heard about that too! Is there an updated version for ipv6?
That file would be ungodly large. There are 2^128 possible addresses, each weighing in at 128 bits, 16 bytes. 16 bytes times 340 trillion trillion trillion. That puts us around 5.44 trillion Zettabytes. The estimates I’ve seen for worldwide data storage sit aroun 60-70 zettabytes.
IPv6 version is just a Python script that generates random 128-bit integers. Eventually you’ll hit a valid IPv6 address!
ipv4 [0,255].[0,255].[0,255].[0,255]
ipv6 [0000,ffff]:[0000,ffff]:[0000,ffff]:[0000,ffff]:[0000,ffff]:[0000,ffff]:[0000,ffff]:[0000,ffff]
This excludes all the ipv4 ips that have a 0 in the 2nd, 3rd, and 4th octets. Sorry but we’re going to have to revoke your Network Engineering credentials.
thanks, fixed
Not to nitpick, but an IPv6 address is represented as eight groups of four hexadecimal digits separated by :. Like 2001:0db8:3333:4444:5555:6666:7777:8888.
Omg, that’s twice now I’ve messed it up. Fixed.
127.0.0.1, I’m an introvert
0.0.0.0/0one of them has a 7 I’m pretty sure
wow don’t doxx me plz
/32
That’s only 1 ip (single host)
