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    Can I use the first IP in a subnet, for instance 192.168.0.0?

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    • scottalanmillerS
      scottalanmiller @1337
      last edited by

      @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

      Not according to the protocol. That is the network address, not a host address. So it could introduce all kinds of problems.

      1 Reply Last reply Reply Quote 1
      • scottalanmillerS
        scottalanmiller @Emad R
        last edited by

        @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

        Broadcast is the highest number of the subnet, the network address is the lowest.

        1 Reply Last reply Reply Quote 0
        • scottalanmillerS
          scottalanmiller
          last edited by

          I don't know of any use of the network address, so I can imagine some equipment allowing it. But I wouldn't, it is just asking for trouble.

          1 Reply Last reply Reply Quote 3
          • wrx7mW
            wrx7m
            last edited by

            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.

            scottalanmillerS 1 Reply Last reply Reply Quote 0
            • scottalanmillerS
              scottalanmiller @wrx7m
              last edited by

              @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.

              wrx7mW 1 Reply Last reply Reply Quote 0
              • wrx7mW
                wrx7m @scottalanmiller
                last edited by

                @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

                JaredBuschJ scottalanmillerS 3 Replies Last reply Reply Quote 0
                • Emad RE
                  Emad R @1337
                  last edited by Emad R

                  @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

                  1 Reply Last reply Reply Quote 1
                  • JaredBuschJ
                    JaredBusch @wrx7m
                    last edited by JaredBusch

                    @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.

                    wrx7mW 1 Reply Last reply Reply Quote 3
                    • scottalanmillerS
                      scottalanmiller @wrx7m
                      last edited by

                      @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.

                      1 Reply Last reply Reply Quote 0
                      • scottalanmillerS
                        scottalanmiller @wrx7m
                        last edited by

                        @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.

                        wrx7mW 1 Reply Last reply Reply Quote 0
                        • wrx7mW
                          wrx7m @JaredBusch
                          last edited by

                          @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.

                          scottalanmillerS 1 Reply Last reply Reply Quote 0
                          • wrx7mW
                            wrx7m @scottalanmiller
                            last edited by

                            @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.

                            1 Reply Last reply Reply Quote 0
                            • scottalanmillerS
                              scottalanmiller @wrx7m
                              last edited by

                              @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.

                              wrx7mW 2 Replies Last reply Reply Quote 0
                              • wrx7mW
                                wrx7m @scottalanmiller
                                last edited by

                                @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.

                                scottalanmillerS 1 Reply Last reply Reply Quote 0
                                • scottalanmillerS
                                  scottalanmiller @wrx7m
                                  last edited by

                                  @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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                                  • wrx7mW
                                    wrx7m @scottalanmiller
                                    last edited by

                                    @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.

                                    scottalanmillerS 1 Reply Last reply Reply Quote 0
                                    • scottalanmillerS
                                      scottalanmiller @wrx7m
                                      last edited by

                                      @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.

                                      wrx7mW 1 Reply Last reply Reply Quote 0
                                      • wrx7mW
                                        wrx7m @scottalanmiller
                                        last edited by

                                        @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.

                                        scottalanmillerS 1 Reply Last reply Reply Quote 0
                                        • scottalanmillerS
                                          scottalanmiller @wrx7m
                                          last edited by

                                          @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?

                                          JaredBuschJ wrx7mW DashrenderD 3 Replies Last reply Reply Quote 0
                                          • JaredBuschJ
                                            JaredBusch @scottalanmiller
                                            last edited by

                                            @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

                                            wrx7mW 1 Reply Last reply Reply Quote 0
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