Can I use the first IP in a subnet, for instance 192.168.0.0?
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
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@Pete-S said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@Emad-R said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@Pete-S
no it is reserved for broadcast stuff. not recommended, i think it is called broadcasting IP
I think you are mistaken it for the last IP address which is the broadcast address. So 192.168.0.255 in this case.
You couldnt let that pass, you have to make me look like idiot.
YOU WANT THE TRUTH, fine i will give it to you. the first IP is reserved for FBI and CIA, here you go
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
That is wrong, those are not network or broadcast addresses in that subnet. They are simply network addresses for hosts.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
Yeah, but "traditional" /24s don't exist in there. The numbers you are avoiding are normal host addresses and in no way network or broadcast numbers. Avoiding them makes no sense, you are just losing numbers.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
Like @Pete-S I use a /22.
You use one, but are treating it like several spanned /24s. That's not how it works. You are thinking like it is the mid-1990s and there are still classes.
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@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
That is wrong, those are not network or broadcast addresses in that subnet. They are simply network addresses for hosts.
Correct. I know that. I saw something a long time ago that said that some devices can't handle those, so I blocked them out. Don't remember where, but it didn't hurt.
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
Like @Pete-S I use a /22.
You use one, but are treating it like several spanned /24s. That's not how it works. You are thinking like it is the mid-1990s and there are still classes.
I know it isn't how it works. Initially, I said that some devices didn't like them.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
That is wrong, those are not network or broadcast addresses in that subnet. They are simply network addresses for hosts.
Correct. I know that. I saw something a long time ago that said that some devices can't handle those, so I blocked them out. Don't remember where, but it didn't hurt.
Maybe in the late 1990s there were still garbage services that weren't IPv4 compatible yet. But that can't possibly be the case today, no one would be able to use those things.
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
That is wrong, those are not network or broadcast addresses in that subnet. They are simply network addresses for hosts.
Correct. I know that. I saw something a long time ago that said that some devices can't handle those, so I blocked them out. Don't remember where, but it didn't hurt.
Maybe in the late 1990s there were still garbage services that weren't IPv4 compatible yet. But that can't possibly be the case today, no one would be able to use those things.
That's good that is no longer a thing.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
In my DHCP scope (for a /22 subnet), I created several address pools which omit the network and broadcast addresses, so they won't be assigned.
Even if they are in scope, those two should never be able to be assigned. It would be a broken DHCP implementation that allowed it regardless. Since hitting the broadcast should cause all the machines to respond, it would wreak havoc with your system if that happened.
How many address pools did you make? There is only one network and broadcast number.
Like @Pete-S I use a /22. I was referring to what would be a traditional network and broadcast of a /24, of which there are a few. For instance, If I have a 192.168.0.0/22, it would span 192.168.0.0-192.168.3.255. I omit 192.168.0.255, 1.0, 1.255, 2.0, 2.255 and 3.0
That is wrong, those are not network or broadcast addresses in that subnet. They are simply network addresses for hosts.
Correct. I know that. I saw something a long time ago that said that some devices can't handle those, so I blocked them out. Don't remember where, but it didn't hurt.
Maybe in the late 1990s there were still garbage services that weren't IPv4 compatible yet. But that can't possibly be the case today, no one would be able to use those things.
That's good that is no longer a thing.
Yeah, can't have been for a really long time. Since nearly everyone, especially outside of the SMB, has been using non-/24 for decades now, they'd run into it constantly. And since it causes a "not compatible with the Internet protocol" issue, it's hard for anyone to defend it
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
I finally got to retire that thing last year.
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@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
I finally got to retire that thing last year.
What? WTF was it hooked to?
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
I finally got to retire that thing last year.
What? WTF was it hooked to?
They make BNC to RJ 45 adapters
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@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
I finally got to retire that thing last year.
What? WTF was it hooked to?
A dot matrix printer that printed checks from our ERP system. I got a brand new identical replacement printer (when the original one was dying) that had an ethernet port and the VAR couldn't get it to work properly. So, I had to end up connecting it back to the ancient directjet via centronics. My new switches didn't support 10Base-T, so I had to setup a 5-port switch and connect it to that. PITA.
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@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@wrx7m said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@scottalanmiller said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
1990s there were still garbage services
I do remember that I was not able to change the SNM on an old HP jetdirect print server that we had connected to some dot matrix printers via centronics connectors. It was 10base-T and also had a BNC connector on it.
Yeah, 10Base-T and BNC was early 1990s. By 1997 we were already way, way past that stuff even in small, cheap deployments.
I finally got to retire that thing last year.
What? WTF was it hooked to?
They make BNC to RJ 45 adapters
This one actually had both connectors. I just used the RJ45.
Edit: It was similar to this one, but mine had 3 parallel ports.
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@Pete-S said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
Is it possible / bad practice to use the first address in the network, for instance 192.168.0.0 (netmask 255.255.255.0) ?
If I remember correctly a long time ago it wasn't possible but nowadays it is. I never use it but when you have small subnets like /29 it could be nice.
@Pete-S : The short answer is No. The longer answer is that it depends on the math.
In 192.168.0.0/24, 192.168.0.0 is the network address... 192.168.0.255 is the broadcast address.
In a 192.168.0.0/23, 192.168.0.0 is the network address, and 192.168.1.255 is the broadcast address.... 192.168.1.0 is a usable IP address in that network.
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@dafyre said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@Pete-S said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
Is it possible / bad practice to use the first address in the network, for instance 192.168.0.0 (netmask 255.255.255.0) ?
If I remember correctly a long time ago it wasn't possible but nowadays it is. I never use it but when you have small subnets like /29 it could be nice.
@Pete-S : The short answer is No. The longer answer is that it depends on the math.
In 192.168.0.0/24, 192.168.0.0 is the network address... 192.168.0.255 is the broadcast address.
In a 192.168.0.0/23, 192.168.0.0 is the network address, and 192.168.1.255 is the broadcast address.... 192.168.1.0 is a usable IP address in that network.
No that’s not how that works. The first address in a subnet is never usable. The last address in a subnet is never usable. There is no in between. Every single subject has exactly one first address and exactly one last address.
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@JaredBusch said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@dafyre said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
@Pete-S said in Can I use the first IP in a subnet, for instance 192.168.0.0?:
Is it possible / bad practice to use the first address in the network, for instance 192.168.0.0 (netmask 255.255.255.0) ?
If I remember correctly a long time ago it wasn't possible but nowadays it is. I never use it but when you have small subnets like /29 it could be nice.
@Pete-S : The short answer is No. The longer answer is that it depends on the math.
In 192.168.0.0/24, 192.168.0.0 is the network address... 192.168.0.255 is the broadcast address.
In a 192.168.0.0/23, 192.168.0.0 is the network address, and 192.168.1.255 is the broadcast address.... 192.168.1.0 is a usable IP address in that network.
No that’s not how that works. The first address and a subnet is never usable. The last address and a subnet is never usable. There is no in between. Every single subject has exactly one first address and exactly one last address.
That is what he is saying. The network is 192.168.0.0, so 192.168.1.0 is usable.
