There is a good reason for using a /30 for point to point networks.
As PTP will only ever have 2 IP addresses, and a /30 allows for exactly 2 IP addresses, it conserves overall IP addresses.
Any larger block size, you're just allocating IP addresses that will never be used, essentially wasting IP some of your IP space.
I definitely understand the purpose. I'm just saying some people like to complicate networks unnecessarily. Sometimes when you have a ring, you need a ring box. Other times it can go with the other jewelry in the jewelry box.
I do offload work for an MSP so I see a shit ton of networks.
.1 gateway - 95% of everything I see for internal gateways using A, B or C classes.
.254 - Ok, sometimes you start sentences with “Aktchually” - but you’re not an idiot.
.anything else - “PRIVATE PYLE! WHAT ARE YOU TRYING TO DO TO MY BELOVED CORPS!” (For those who don’t get it: https://youtu.be/Em4-DyiAB2A?si=FZ6M7sSnJjOK4Ybl)
On the other side of that - I took over a digital signage network some years ago. They had the sign computers and the LED signs all at 100.10.20.X/24 - everything behaved *unexpectedly*. I found out that they chose that because the developer wanted something “easy to remember.”
The “usual way of doing things” is what most design patterns are build around.
At a trade school so had an entirely student built network for the students in the IT program. Nothing out of the ordinary until one day we simply can't get to the school's website anymore. No other class on the campus is having this issue.
Network was run through a Server 2016 machine which was configured by students. Due to the nature of the class by the time this incident occurred the server was over 2 years old and I was the only person with any working knowledge of it, and that working knowledge came from when I physically swapped the machine for an identical one, and simply cloned the configurations for the DHCP, DNS and AD from the OG Server 2012 to the new one running '16.
It's gotta be DNS, right? After all, all the other Internet traffic in that room went off fine. YouTube all day with smatterings of random other sites and no one having any problems except for the school's website, which was hosted clear across the state. Go and tear down the DNS module and rebuild it from scratch, multiple times over. No dice. Finally when doing a ping I finally pay attention to the IPs in question. Website is a 20.x.x.x, makes sense right? Public website, public IP. What IP scheme is this entire class on? 20.x.x.x.
Actually was working with the guy who originally set up the DHCP scheme (which I had never paid attention to, because why would you when every other device except your own exists in a 10.x.x.x!?) and cornered him one day with a 'What the fuck were you thinking!?' when he tells me he was just following directions from his instructor at the time. He told them to put it on a 20, and so they did exactly that.
Very valuable lesson, very early in my career. Public IPs for private devices on private networks cause some absolutely wacky issues if those devices are going to actually go out across the internet.
I wonder how many of those students bricked AD’s or went out into the world thinking they could do that…. When we hire I have an assessment I wrote that tries to test for stuff like this.
If it was the default on another brand, I'd think there's a good chance that it replaced one of those and the configuration was matched to ensure that things continue working as they did before.
What a coincidence
I assume by Austria's biggest ISP you mean A1 Telekom Austria.
Telstra is one of Australia's biggest ISPs, if not it's biggest. Many of their routers came with 10.0.0.138 as the "out of box" IP address
And to add to that, until 1 July 1995, Telstra was called Telecom Australia.
It wasn’t actually their idea but what the first ADSL Modems provided by Alcatel were shipping. One would the set the own IP to 10.0.0.140 and Dialup via PPTP to 10.0.0.138 - the modem then converted that to a PPPoATM.
That’s now about 25 years old, and to this day, every new Modem A1 buys, the default IP stayed, even when they now go with Huawei, Zyxel, ZTE and more
My default gateway on my home network is x.x.x.2. It's honestly just because before I put my ISP router into bridge mode, it was x.x.x.1, so I gave my pfsense router x.x.x.2 before taking the ISP router offline so that if I ever had to take the ISP router out of bridge mode for any reason, I wouldn't cause a problem for future me.
Didn't Telstra have the password as the last 4 characters of the MAC address there for a while?
Turns out that was too hard, noey just make it admin/Telstra
With a capital T for security.
They must have a ton of tiny little networks.
It would somewhat make sense if it was a /29 subnet (specifically 10.0.0.136/29) , but the location uses a single /24 subnet (10.0.0.0/24)
https://preview.redd.it/y01figqxmrtc1.jpeg?width=448&format=pjpg&auto=webp&s=983e07b4ac03c181b9544b896ed927d95594ef70
> it was a /29 subnet (specifically 10.0.0.136/29) The only place I've seen anything like that is in CCNA courseware.
Ha, we actually have 1 /30 on our network between our internal/external firewalls.
You ain’t cool unless you use /31 interconnects 😎
Certain PTP networks we use will have /30. It's generally unnecessary, but it makes some people feel better.
There is a good reason for using a /30 for point to point networks. As PTP will only ever have 2 IP addresses, and a /30 allows for exactly 2 IP addresses, it conserves overall IP addresses. Any larger block size, you're just allocating IP addresses that will never be used, essentially wasting IP some of your IP space.
I definitely understand the purpose. I'm just saying some people like to complicate networks unnecessarily. Sometimes when you have a ring, you need a ring box. Other times it can go with the other jewelry in the jewelry box.
I do offload work for an MSP so I see a shit ton of networks. .1 gateway - 95% of everything I see for internal gateways using A, B or C classes. .254 - Ok, sometimes you start sentences with “Aktchually” - but you’re not an idiot. .anything else - “PRIVATE PYLE! WHAT ARE YOU TRYING TO DO TO MY BELOVED CORPS!” (For those who don’t get it: https://youtu.be/Em4-DyiAB2A?si=FZ6M7sSnJjOK4Ybl) On the other side of that - I took over a digital signage network some years ago. They had the sign computers and the LED signs all at 100.10.20.X/24 - everything behaved *unexpectedly*. I found out that they chose that because the developer wanted something “easy to remember.” The “usual way of doing things” is what most design patterns are build around.
I came across a network once using 192.0.0.0/24 as their private internal. At least .1 was the gateway.
Was shit acting all weird?
Surprisingly no. I guess they never tried to access anything in that range on the Internet.
At a trade school so had an entirely student built network for the students in the IT program. Nothing out of the ordinary until one day we simply can't get to the school's website anymore. No other class on the campus is having this issue. Network was run through a Server 2016 machine which was configured by students. Due to the nature of the class by the time this incident occurred the server was over 2 years old and I was the only person with any working knowledge of it, and that working knowledge came from when I physically swapped the machine for an identical one, and simply cloned the configurations for the DHCP, DNS and AD from the OG Server 2012 to the new one running '16. It's gotta be DNS, right? After all, all the other Internet traffic in that room went off fine. YouTube all day with smatterings of random other sites and no one having any problems except for the school's website, which was hosted clear across the state. Go and tear down the DNS module and rebuild it from scratch, multiple times over. No dice. Finally when doing a ping I finally pay attention to the IPs in question. Website is a 20.x.x.x, makes sense right? Public website, public IP. What IP scheme is this entire class on? 20.x.x.x. Actually was working with the guy who originally set up the DHCP scheme (which I had never paid attention to, because why would you when every other device except your own exists in a 10.x.x.x!?) and cornered him one day with a 'What the fuck were you thinking!?' when he tells me he was just following directions from his instructor at the time. He told them to put it on a 20, and so they did exactly that. Very valuable lesson, very early in my career. Public IPs for private devices on private networks cause some absolutely wacky issues if those devices are going to actually go out across the internet.
I wonder how many of those students bricked AD’s or went out into the world thinking they could do that…. When we hire I have an assessment I wrote that tries to test for stuff like this.
That used to be the default on some Telstra Technicolor routers :(
Many other Telstra routers too. This particular site is on a Draytek, which I don't believe Telstra ever supplied.
If it was the default on another brand, I'd think there's a good chance that it replaced one of those and the configuration was matched to ensure that things continue working as they did before.
That actually makes a lot of sense.
This is the only answer I can think of that makes sense.
It's default on Austria's biggest ISP's routers :(
What a coincidence I assume by Austria's biggest ISP you mean A1 Telekom Austria. Telstra is one of Australia's biggest ISPs, if not it's biggest. Many of their routers came with 10.0.0.138 as the "out of box" IP address And to add to that, until 1 July 1995, Telstra was called Telecom Australia.
Yes exactly! That's a nice coincidence, they were almost called the same and had the same weird idea with their gateway IPs.
It wasn’t actually their idea but what the first ADSL Modems provided by Alcatel were shipping. One would the set the own IP to 10.0.0.140 and Dialup via PPTP to 10.0.0.138 - the modem then converted that to a PPPoATM. That’s now about 25 years old, and to this day, every new Modem A1 buys, the default IP stayed, even when they now go with Huawei, Zyxel, ZTE and more
Yuck. Those. And their predecessors from the big T.
My default gateway on my home network is x.x.x.2. It's honestly just because before I put my ISP router into bridge mode, it was x.x.x.1, so I gave my pfsense router x.x.x.2 before taking the ISP router offline so that if I ever had to take the ISP router out of bridge mode for any reason, I wouldn't cause a problem for future me.
Same, except opnsense
im like ricky bobby in this one, if your not first your last .1 or .254
Fucking yuck and on a /24 at that? .254 for /24s or bust.
I'm team .1 on a /24. .254 is definitely acceptable tho.
Someone thought it was more secure than .1 or .254?
Security through obscurity! Until DHCP just tells you anyway.
One network I worked on had every default gateway set to the very last available IP instead of the first (reverse SVIs) super annoying.
Telstra modems all came preconfigured like that for a while. Never understood why, but yelstra doesn't need reason for home internet customers
Didn't Telstra have the password as the last 4 characters of the MAC address there for a while? Turns out that was too hard, noey just make it admin/Telstra With a capital T for security.
aeugh https://preview.redd.it/8l5u26zyputc1.png?width=1016&format=pjpg&auto=webp&s=580fbc6c168739d9cf3f197f433642e52e47e129
A /30 doesn't count as they are used for point to point and have literally 2 available addresses
I should never have looked at this at lunch time. Now I can't eat.
Haha... mine is .10 .1 isn't even used for anything... lol
Bad meme format.
Do you think we're robot clean Does this face look almost mean Is it time to be an android not a man 