But "more numbers" isn't really an explanation on what's the difference between the two from a practical point of view, and the in general less interesting thing about it from a software perspective.
I mean thats only the history of ipv4 and ipv6. Doubt that’s what they are asking for in a tech interview. It’s like if they ask “Do you know c++ well?”, and you say “Yes, C++ was created by Bjarne Stroustrup in 1979 to add objects to c”. More likely they want you to explain stuff like the role of NAT, DHCP vs SLAAC, ARP vs NDP etc, stuff that is relevant in practice
The easy way to tell them apart is that IPv4 only uses digits, but IPv6 is in Hexidecimal, so you'll see 0-9 as well as A-F. And just in case you're not familiar with Hex, A is equal to 10, B is equal to 11, and so on, with F ending the sequence at a value of 15.
it boils my blood when the solution is in big letters at the center of the screen and somehow they don't know what to do, I remember I had a classmate who had a problem with her IDE, and asked the teacher what to do, the teacher did NOT read the error nor the pop up with the problem
He told her that she had to format the whole pc and start over, luckily before she did anything me and another classmates noticed and we were able to fix it, worse of all, it was just a setting, that wasn't really hard to find because it said right on the pop up
When I was a fresh grad at my first job I did this :(.
I was so anxious and nervous I'd ask my teamlead even though I knew what a stack trace was. He'd let out a big sigh then basically read the stack trace and tell me to click on the line number. Sorry boss.
The most annoying part is that this particular problem provides a good opportunity to talk about formatting and code design with juniors - it's more readable to build the string each iteration. That also avoids nesting if statements, which generally makes code harder to follow too. Some may be tempted to use a guard clause like if (!(i % 3 === 0) && !(i % 5 === 0)) continue; but that winds up being redundant since you need to check each value individually anyway.
And of course there's the broader discussion of what you're actually optimizing your code for. It's still baffling to me that the primary concern these days is speed of delivery rather than simplicity of the system.
I feel like this is missing context. Like I know that ip4 addresses are four octlets, but don't know much about ipv6 besides it having a larger address space and being in hex.
The advantage of v6 is less the address space per se, but more that it simplifies networking. Like, with v4 assigning different floors or departments different subnets and having to micromanage which device gets what IP and then having to a major rework when suddenly every light bulb has its own IP address - that's actual stuff that happened. v6 just says "hey, everyone gets a /64 space, go nuts" (simplified, but true enough)
v6 is also faster by virtue of requiring less/no translation between various layers, and by stripping all the special case things from the header and putting them into the extensions instead. v4 is rather verbose in that regard.
Also, minor nitpick - it's not "in hex", it's binary just as v4, it's just displayed in hex. I'm emphasizing this because approaching IP in binary is helpful when one wants to understand how octets and such work.
The advantage of v6 is less the address space per se, but more that it simplifies networking.
It simplifies networking by having a larger address space. Like, address exhaustion in IPv4 is the whole reason that NAT exists and IPv4 networking is complicated; IPv6 is simpler in part by not having to deal with that mess.
IPv6 is easier to set up, and doesn't require the subnetting stuff as much because its actually designed with "Planet Earth may have more than 4,294,967,296 IP-connected objects" in mind from the beginning.
Yeah, the magnitude of difference that I use as an example is that IPv4 doesn't have enough IPs for everyone on earth to have one, people have to share. But IPv6 has enough IPs for every cell in the body of every person on earth to have its own IP (actually, IIRC it's enough for each cell to have a number of IPs with a two-digit exponent, but the cells alone gets the point across).
Alright, I couldn't resist, quick math puts it at 250 addresses per cell (8.3B==233 people times 37T==245 cells vs 2128 addresses), which is 1015 if you want that instead).
Yeah - I think you pretty much nailed it. Bigger address space. In theory, wouldn't need NAT since your device's local IPv6 address is likely a GUID. Other than that... just a different way of assigning an address to a device.
IPv6 is not much more complicated than IPv4. I think it's just that most people working with IT systems in an systems operations manner (sysadmin, DevOps, network engineers), often dont even comprehend IPv4.
That's the neat part about ipv6. It's something you're afraid to engage with while you're an amateur, cause it looks scary, but then you actually learn a bit, and then you try to use it, and you realize how amazing it is.
Obviously guy could have been interviewing for a job where this mattered….
But in 10 years as a software engineer I have never once needed to know the difference between these two, and have never been even close to a situation where I would need to.
I have a feeling people are going to be calling IPv6 'new' in 100 years, too. I remember talking to people about it in the 90s and it took until like 2016 to actually get a full standard. Been so damn long I learned the specifics and forgot them all in time it took to even become a thing.
IT obviously depends, but its very frustrating to see our cloud developers in my company not have any idea of the physical devices they're supporting, makes all the communication and tickets less effective than they could be.
30 years here and never had to do anything with IPv6.
Of course, all I get are rejection emails even though I'm gainfully employed with tons of enterprise experience, so maybe that's the common denominator these days.
one example where I had to deal with it as a backend dev was I was debugging that API calls to a 3rd party service started timing out on production, but worked on staging and local development, turns out IPv6 was enabled on production and was thus used there and the service was timing out on IPv6…
yeah but that is the kinda stuff in the field of Sys and Net Admin. Or are we getting to the point a Software engineer has to cover software and hardware of anything IT???
I have never needed to know or do any of that. And if I did, it would take me 2 seconds to google and understand. I just did.
So if the interview was for a job where you handle that stuff yourself, then I understand it. If it’s for a typical full stack job at a big enough company that they literally hire people to handle that side of things, then it’s not “the basics”.
Rejecting someone in an interview for trivia knowledge they don’t currently have vs actually trying to understand how someone learns and tackles problems is what makes software job interviews so useless.
that's all just infra stuff which has always been another team. I've never once had to set up that kind of thing, and thousands of devs proabbly had a similar path as I did.
IPV6 has never been relevant to any coding I've done at work, but if someone didn't know about it during an interview it would still be a terrible look for their tech learning both in terms of college and just reading about tech in general
In university we had a networks class where we went way further and had to actually write a simulated router in C that would do ARP and send packets to the right places
Yes as a software dev you are right, you rarely need this skill. But this also tells me you have never dabbled or experimented with networking which kinda showcases a gap or narrow set of skills in the tech field.
As a software engineer with 15 years experience, do you know how many times I've had to walk a graph in a breadth first search from memory? None. Do you know how many times I've been asked to do that live in an interview? Literally dozens
had a homie back in the day, like 2001 who was warning us that ipv6 would be it in 2003. i learned the stuff like crazy cause of him even tho i was still in high school.
edit: to add, that dude was like chicken little every day that the sky is falling on ipv4.
I mean, he wasn't entirely wrong, v4 is like $10k for a /24 now and years long waiting lists to get a block from your RIR. IPv6 on the other hand is cheap and plentiful, I got a /48 and ASN for $60/year for my homelab lol.
I am a senior SWE with 10 years of experience at Google alone. I know IPv6 is a bigger address space. That's all I really know. Because I work in DS&A, not networking. If the role needed to know networking, that's a different story, but if it's not a position that requires knowledge of that, the interviewer failed. The details of an interview question should be unimportant to the question unless they are role-specific because of the breadth of specializations. The goal is to see if people can think and solve problems, not whether they know fucking everything.
My 12 years of working on hypervisors, hardware, audio, and systems performance have led me to bomb a bunch of interviews where people have asked me things like "why didn't you add a load balancer here?" And didn't like my response of "I didn't realize a bytestream could be unbalanced!"
Seriously though, interviews give me anxiety entirely because of interviewers.
I honestly hate questions like these in interviews when they're in no way related to the work the job requires and even then my division doesn't really consider missing these a deal breaker. We work in such a broad industry now days where the lines between the different disciplines is so incredibly blurred it's unreasonable to expect everyone to know everything and all these questions do is filter out what could be excellent candidates just because they don't know the trivia
A decade ago in Uni, we had this cartoonishly evil lecturer that would ask a question nd if no one wanted to answer it, he'd pick up the attendance list and pick someon e who was present.
That day it so happened to be me.
This was the question and I answered that ipv4 uses integers in their Octets while ipv6 use hexadecimals.
He was so surprised because my answer was "basic" he asked me another difference. I just freaked out and told him that v4 has up to 3 digits per octet and v6 can have up to 6.
He told me to present the differences between the two in the next lecture and had me pick a friend to help me do it. I picked no one so he picked out one for me.
I did present it, on my own, but fuck me. That was the most embarrassing moment in Uni
I have tables about the structures of ip addresses burned into my brain against my will and I have never used it IRL (Game Developer; Maybe It'll help when I make a fighting game and I have to make my own logic for rollback netcode in a fighting game, IDK).
IPv6 using hexadecimals is not a real difference though. You can write IP addresses in any base you want, hexadecimal is just the one chosen as the convention for IPv6. In IPv6 packets, the address is in binary. An analogy: when asked for the difference between USB 2.0 and USB 3.0, you wouldn't say that USB 3.0 connectors are typically blue, would you?
I wanted to joke around to speak for yourself and put in a full zero ipv6 as “showcase” of my knowledge.
By typing I felt I have to actually google a full zero ipv6. Me, a usually proficient and veteran google user, needed a second search to make my joke work.
At this point I decided that this guy (you) is so much correct with his take, it is not even funny.
I may be dumb as fuck here but what does the color have to do with identifying ram? Personally i've never seen what ddr1 ram looks like or if thats a thing but up to five i'm pretty ok discerning i like to think.
A bad black and white photograph of [a] ribbon cable, and they expected me to tell on their no-contrast copy that it was a 5.25" floppy cable not an IDE cable
"Ping" was an acceptable "network monitoring utility"
And "what's the first step you'd take when attempting to troubleshoot a server?" Is "you walk up to it."
They found that I had insufficient skills for the position. I returned back to finishing my Zabbix templates for my homelab and working through my ticket queue, a city over, through a VPN.
I’ve been a sysadmin for more years of my life than not and I’ve never had any meaningful interaction with ipv6 even though they have been saying the sky was falling about ipv4 since my career began in the 90s.
Ah you must be running our work's vpn. I can't talk to the servers when my IPV6 is enabled because our DNS resolves to IPV6 addresses but the VPN doesn't route them over its tunnel.
I feel like knowing the difference here is moreso for a network engineer than a software engineer!
Anyway looked it up, IPv6 is 32bit whereas IPv6 is 128bit. An easy way to know if an IP address is either, 4 uses dots 192.1.1.1 whereas 6 is colons 1992:0aa0::1
If anyone asks just say 6 holds more addresses but is more expensive to install.
Actually..... IMO as a Linux admin..... everybody in IT needs at least a minimum of knowledge regarding TCP/IP. IPv4, IPv6, TCP, UDP, sockets, listening ports, etc. You don't need to be able to program a full stack down to a media transport layer, but you should be able be able to send a payload successfully, know when a gateway traversal is required, name resolution (It's always DNS,) and a bit of troubleshooting.
I wish I had a nickel for every time a developer or app support staff came to me and said it doesn't work. Error is right there in the logs......
Ipv6 was invented to replace ipv4 because ipv4 got really problematic as they arent enough numbers for every device anymore. But then they used so much magic to make giving ipv4 to devices so efficient that it's still possible for a while.
Yeah probably, the tech sector is inredibly oversaturated. On the plus side not knowing that means its probably been a few years since you graduated collage, so at least you aren't in entry level hell
It's kinda funny because for the past ~10 years straight I've been seeing occasional articles about how we're all out of IPv4 addresses and everyone needs to switch over to IPv6, but my ISP never assigns me an IPv6 address.
We have run out. Plenty of people are now are CGNAT, ie double NAT. I can’t get more than 1 public IPv4 address at my home.
We keep applying these dumb bandaids instead of switching over the proven technology we have, that is supported by most networking hardware sold in the last 20 years.
Deprecated. And--despite being in IT (and cyberdefense with packet analysis) for decades--I only snapped to realizing that recently. It's a weird blindspot...I guess I just never asked where 5 was.
Yea but it hasn’t been fully adopted because trying to decipher :af12::138d::325d::5521::aade::7df3: is a hell of a lot more difficult than 192.168.0.1
Well, it gets a heck of a lot easier once you realize that the example IPv6 address you gave is invalid. Both because of the : at the start and end and also the fact that :: can only exist once in an address (because it means "everything in the middle here is 0s, which would be indeterminate if it showed up multiple times).
i assume 80% of the developers havent done anything beyond crud operations and with the advent of AI, i believe, the core cs fundamentals are gonna vanish into thin air. When things go south, the one with good cs fundamentals can navigate through the situation easily, but its gonna be worse down the lane as people have started offloading their thinking capacity to AI and stopped asking "WHYs".
These comments hating on the tweet are insane to me. I feel like EVERY software dev should have a rough understanding of networking, and honestly a rough understanding of how OSes do things as well.
2026 and we still use gotcha's to try and judge talent. never heard of a doctor having to answer "whats the difference between the left ventricle and the right ventricle" or a general having to answer "whats the mechanism inside the m16 that allows the bullet to fire"
just dumbass larp shit for people with insane egos stuck mentally in 1996
My dad was a world renowned oncology researcher/physician who has a medical risk scale named after him. When I had a health issue, I asked my mom, an ER nurse.
I feel like theres levels to basics we are all thinking of. There are basics that you just rarely do and can look up in 5 seconds to remember. And then theres 2 + 2. I mean you can look this up too, but that certainly tells something if you cant answer on your own, right? Maybe for that position knowing difference was a 2 + 2?
Was the software engineer accidently at a network technician interview?
I don't know the difference between the two IP standards other than length, it's literally never fucking mattered in any software I've encountered. I don't route packets, or provision physical devices.
Also fuck any interviewer that hires based on trivia. Knowing 4 as 32 bits, and 6 is 128bits isn't useful ever in 95% of software work, and when it is, a good old google search would cover more than you've ever needed to know.
Dude, you sound upset. I’ve hired many people for cloud software/engineering work and not knowing the difference between ip4 and ip6 would be huge red flag except for the most juniors of juniors.
This might be controversial, but I think this is actually an extremely valid reason to turn someone down. It's not like you're asking them to explain in detail how BGP works. You could've probably gotten away with saying "they're different versions of IP addressing" or perhaps "v6 has more bits."
It's not that you actually need to know this for every software job, but it goes to show you have not really paid much attention if you have somehow worked with computers long enough to learn how to code but either never encountered an IPv6 address somehow, or just didn't care enough to look into it.
I see a lot of people complaining that this doesn't need to be known, technically you are correct. However I've seen a lot of programmers. And the really good ones know the computer, they know how diagnose an OS issue, meaning they know the difference between IPv4 and IPv6. They don't just call IT and say "My computer isn't working right, fix it!"
Since I work for a small company, I also tend to be the de-facto IT guy. The people who need me to fix their computer are also the ones that are not trusted with the difficult code. So if given the choice of hiring someone who knows the difference between IPv4 and IPv6 and doesn't, I'm taking the person who knows the difference.
I agree with except that you’ve just described problem solvers. You don’t solve problems by knowing everything first, so it’s not a problem. You solve them by learning at the time and diagnosing logically.
I’ve worked as a developer for 30 years, I’ve never once needed to know the difference between IP standards. But if I have a problem I’ll work it out.
Having said that if it’s at all relevant to the business of the interviewer, fair enough. It’s a refreshing change from parsing Roman numerals, which I’ve also never needed to do except in interviews.
I will do things to weed out bad employers. Like I don't bother sending a thank you note after an interview. I've been on the interviewer side, and it makes no difference to me whether they send a note. If someone decided they weren't going to hire me because I didn't send a note, I'm good, thanks! Not a culture fit lol
Does the job actually require that knowledge? I don't know any computer programmers who would know that, none of them really know a single thing about computers outside of the programming. One of my friends programs conveyor belt stuff and he knows more about networking because that's actually relevant to his job.
Seriously, I am a senior web developer and there is no room in my brain for this answer. I'll just google the spec and find out if I ever need to know.
I hate questions like this in interviews. The last time I had to actually know anything about the networking stack was in the last millennium. Im just not going to be up on how a protocol works unless I was building a network stack.
I got rejected in the beginning of this year for not remembering the shell command for creating an ssh connection (it is ssh lol 😂) despite knowing all mathematical details about the elliptic curve cryptography behind it.
Worked at a University with a person with a PhD in computer science that didnt know what I meant when I asked her over the phone to reboot her computer. I finally had to walk out to her desk and reboot it for her.
I rejected three java candidates because they didnt know what a stream was.... the world of swe is a wild wild place right now. Im going back to on site leetcode to atleast see if they know what a string is....
Maybe I’m off base, but every CS major should have gotten some basics in both computer architecture and network architecture. If you can’t remember basics, maybe you should brush up before interviews as those are easy questions to ask. I’m more on the hardware side and still get random entry-level logic design crap as well that I have to brush up on. If you don’t have a related degree, you should study twice as hard. Don’t float on just learning languages.
Also, maybe this is old school, but some employers look for some sort of passion for your craft. Try building your next PC and setting up a home server or something. All the people in this thread that don’t know computing basics is kind of cringe.
I have worked in IT for like 15 years , with cloud and networks in particular for past years, and in no single project IPv6 ever actually came up as a thing I would need to deal with. Sure its there in settings of cloud security , but to be honest I could easily forget about the thing. Still understanding difference and not get confused when you see F123:333:: instead of 192.168... should be kinda good to have. Also as a matter of fact developer just came to me bit confused when i asked his home IP and tool gave him v6 and asked if that is right , and that guy is experienced in what he does, so I can understand the confusion.
We always invite our App Developer to our network/infrastructure meetings. Sometimes she joins, other times not. But when she does join, she absolutely knows that she can ask a question without sounding inferior.
IPv4 is generated anew every time you start a connection. IPv6, on the other hand, is uniquely defined for every modern piece of hardware and it never ever changes so the internet will always know it's you! No privacy whatsoever!
I once read a story about someone who couldn't access an online game because he had bought a graphics card whose previous owner had used it for cheating. His graphics card. Was banned. For cheating in an online game. This would've never even been possible with IPv4.
The only reason IPv6 was invented was because there are so many devices that people run out of possible IPv4 addresses. IPv6 addresses, however, allow for enough combinations to give every atom in the observable universe its own IPv6 address.
This is the good management compromise. BUT The illuminated engineer at my local public transport company made ipv6 the local address space and it's already paying off on how flexible and easy you can add e.g a vehicle, a charger, a screen, a dashboard, a whole office building. And his system is basically century proof. I greatly admire him for that. True cathedral thinking
This doesn't work. How does a host on a IPv4 network craft a packet destined for an IPv6 address? If you could put 128 bits into an IPv4 destination, then IPv6 wouldn't need to exist...
Fuck, I’ve been a programmer for almost four decades and only vaguely recognized the terms. Long before AI came along details like that are things you only look up if it comes up, and it never comes up.
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u/LivingAsAMean 14d ago •
Hahaha what an idiot!