I don't follow.
It's just the decimal form of a base 256 number with four digits.
Or perhaps it's the decimal form of a base 16 number with eight digits.
This is a valid ipv4 address
41–50 of 101 posts
Re: This is a valid ipv4 address
#42Guys check out this website at http://0x7f000001 hahaha what an idiot made this, that page is shit!
seriously downvoters? how do you walk with that stick in?
Re: This is a valid ipv4 address
#43Re: This is a valid ipv4 address
#44Earlier quoted context omitted.
seriously downvoters? how do you walk with that stick in?
Maybe the downvoters don't get the joke and they think you're insulting their website. :-)
The downvoters probably found a lot of pr0n and warez and (or?) unsavory content at that address. Imagine how painful it would be if you clicked on that and saw the legendary goatse, or tubgirl.
Re: This is a valid ipv4 address
#45not valid
Re: This is a valid ipv4 address
#46The last time this came up on HN, I decided to dig into ping and glibc's resolver stuff to find out exactly why this worked. http://rachelbythebay.com/w/2012/10/13/ping/
That article is focused on ping and glibc but the reason why this works is fundamental to IPv4 itself. All IPv4 address are 32 bit addresses. That's why each number of an IPv4 address that people are familiar with are called octets. They represent 8 bits of the 32 bit address. So if you have 127.0.0.1, then the first octet is 127, the second is 0 and so on. Any representation of this 32 bit number (including the most…
No, it works because the tool allows it by virtue of how it's implemented. Find a different ping or inet_aton implementation and it won't necessarily work.
Re: This is a valid ipv4 address
#47The last time this came up on HN, I decided to dig into ping and glibc's resolver stuff to find out exactly why this worked. http://rachelbythebay.com/w/2012/10/13/ping/
That article is focused on ping and glibc but the reason why this works is fundamental to IPv4 itself. All IPv4 address are 32 bit addresses. That's why each number of an IPv4 address that people are familiar with are called octets. They represent 8 bits of the 32 bit address. So if you have 127.0.0.1, then the first octet is 127, the second is 0 and so on. Any representation of this 32 bit number (including the most…
"if you want to spend time learning about IPv4 right before IPv6 becomes the dominant standard"
Not as much is changing as you think, at least for basic concepts and intro level stuff. Simpler in some ways.
To kick over a real bee hive, as I guy who's used ipv6 for I donno a decade or so now, the main issues are NAT6 love it (noobs) or hate it (folks who know what they're doing), believe it or not its easier to make a statefull firewall than to do NAT, some folks have bizarre ideas about ipv6 netmasks and what other people should be permitted to have, the concept of RFC1918 in ipv6 is more complicated, router advertisements RA love them or filter them, you probably need DHCPv6 or maybe not, and some firewall nuts filter DNS traffic into packets too small to hold AAAA records (but large enough to hold A records) Other than that ipv6 is just obese ipv4, the concepts of subnet and mask aren't changing, you've still got ARP just different address family in the protocol...
(edited to add my favorite topic, hand editing text zone files is probably not the most scalable way to implement reverse (or forward!) DNS for ipv6 from pure PITA perspective. Then again doing things by hand instead of automating is a PITA for ipv4 not just ipv6.)
Re: This is a valid ipv4 address
#48sage
Re: This is a valid ipv4 address
#49The submission is a little misleading; it's traditional on HN to link to an article discussing the principle, rather than simply a demonstration. However, the OP highlights an interesting point. There are other, analogous, unexpected behaviours like this one, such as numeric constants with leading zeros being interpreted as octal, that arise from the ubiquity of the C standard library. You see them in Java all over t…
> Don't think good penetration testers (and malware writers, alas) don't already know about this trick. This was also a popular trick among kids at my high school to work around the web content filter and get on social networks
yeah, some years back there was also some C code in an issue of 2600 (or maybe a bash script? I cant remember) that obfuscated URLs in this manner. The article that the script was attached to actually used school URL filtering as the example case use.
Re: This is a valid ipv4 address
#50I first discovered these 10digit decimal formatted IPv4 address about a year ago when testing/analyzing android apps. Created a quick python scripts to convert back and forth.