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    Is it possible to assign the same static IP for two different MAC addresses?

    Scheduled Pinned Locked Moved DHCP and DNS
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    • johnpozJ
      johnpoz LAYER 8 Global Moderator
      last edited by

      Why don't you just use dns to solve this problem - and just make sure the dns record is updated as the "host" machine moves from one network to another, etc.

      I don't understand why wired and wireless would want to be the same IP - you have given some reasons why you think they should.  Don't agree with them to be honest ;)

      For one - wired and wireless networks from security standpoint could be debated even they should even be the same segment.  My wireless is isolated from my wired network, and you will find that many enterprise setups this is also the case.  Wired and Wireless are rarely the same segment other than the smallest of shops or home setups.

      An intelligent man is sometimes forced to be drunk to spend time with his fools
      If you get confused: Listen to the Music Play
      Please don't Chat/PM me for help, unless mod related
      SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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      • S
        stpq
        last edited by

        @johnpoz:

        Why don't you just use dns to solve this problem - and just make sure the dns record is updated as the "host" machine moves from one network to another, etc.

        I don't understand why wired and wireless would want to be the same IP - you have given some reasons why you think they should.  Don't agree with them to be honest ;)

        For one - wired and wireless networks from security standpoint could be debated even they should even be the same segment.  My wireless is isolated from my wired network, and you will find that many enterprise setups this is also the case.  Wired and Wireless are rarely the same segment other than the smallest of shops or home setups.

        totally agree with you on security issues, i try to isolate the wireless network as much as hardware will allow.

        How would you solve the, lets take the skype session, , dying connections when u change ip than? (u go from wired to wireless) Like dying sessions are pain especially when u have bunch of ssh sessions open and they die…

        s

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        • K
          kejianshi
          last edited by

          Skype comes back up pretty fast - Thats a minor annoyance.

          What are you using the ssh sessions for?

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          • S
            stpq
            last edited by

            skype: minor, but still anoyance…
            ssh...

            well for whats it meant to, beginning with simple remote access, going through x11 export and sometimes some tunneling....

            how is that important for diying of sessions?

            and dont take me wrong, i have dropped same IP for different mac a long while ago, to begin with (i begin with users) because of some os (like window$ whatever version) is not able to take same ip on two ifaces, continuing through migration of dhcp to zeroshell, using pools instead of static definitions of ips for the clients and so and so...  Im just saying that sometimes, specially in small network/home environments it can be useful....

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            • K
              kejianshi
              last edited by

              I think the cure for you might be to install a headless server that doesn't have to move here and there and everywhere to handle all that and just use your laptop for everything else.

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              • DerelictD
                Derelict LAYER 8 Netgate
                last edited by

                Or just get good wireless and stay on it even when docked.

                Chattanooga, Tennessee, USA
                A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                • johnpozJ
                  johnpoz LAYER 8 Global Moderator
                  last edited by

                  "Or just get good wireless and stay on it even when docked."

                  Exactly – here is the thing if your going to be changing networks, you have to expect that a session would die, just reconnect - I don't see an issue here at all.  if I had a ssh session open and I went from wired to wireless - then yeah that session would have to be reopened.  What is the saying you can't fix stupid ;)  Anyone that would think they can maintain sessions while changing their connection type doesn't understand networking ;)

                  Even if you move your IP to a different nic - your session like ssh is still going to die..

                  So your complaint is your ssh client doesn't reconnect for you?

                  As stated to solve your problem don't move your connection - use wireless while docked or undocked, there you go problem solved you never loose your connection ;)

                  An intelligent man is sometimes forced to be drunk to spend time with his fools
                  If you get confused: Listen to the Music Play
                  Please don't Chat/PM me for help, unless mod related
                  SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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                  • K
                    kejianshi
                    last edited by

                    Unless your wireless drops…  Which never happens (-;

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                    • DerelictD
                      Derelict LAYER 8 Netgate
                      last edited by

                      Which is why I said good wireless, not some $19 tp-link from walmart.

                      Chattanooga, Tennessee, USA
                      A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                      DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                      Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                      • S
                        stpq
                        last edited by

                        "Even if you move your IP to a different nic - your session like ssh is still going to die.."
                        ehm, nope..

                        "So your complaint is your ssh client doesn't reconnect for you?"
                        yeah, but do u have any clue how long it takes for ssh to timeout?

                        wireless…. hmm... something like AC than, and even that wont give u gigabit... wire is wire and wireless sux, regardless the price of it..

                        And again, dont take me wrong, as i stated earlier... I  just think, that it can be a valid argument... I mean its implementen in ISC.. its a feature, not a liability...

                        s

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                        • DerelictD
                          Derelict LAYER 8 Netgate
                          last edited by

                          So you want:

                          1: the speed of Gig-E when you're wired
                          2: the convenience of wireless when you're not
                          3: total disregard for the OSI model when you switch between them.

                          Got it.

                          Chattanooga, Tennessee, USA
                          A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                          DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                          Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                          • K
                            kejianshi
                            last edited by

                            I'm convinced personally - I'm switching all my servers to wifi (-;

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                            • S
                              stpq
                              last edited by

                              @Derelict:

                              So you want:

                              1: the speed of Gig-E when you're wired
                              2: the convenience of wireless when you're not
                              3: total disregard for the OSI model when you switch between them.

                              Got it.

                              you are totally right…

                              but look at this: https://forum.pfsense.org/index.php/topic,36066.msg186013.html#msg186013

                              so it still might be possible...

                              and does it violate OSI model to have two interfaces with addresses from the same subnet?

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                              • DerelictD
                                Derelict LAYER 8 Netgate
                                last edited by

                                No.  It violates the OSI model having two interfaces with the same MAC or two MACs with the same IP.

                                Chattanooga, Tennessee, USA
                                A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                                • DerelictD
                                  Derelict LAYER 8 Netgate
                                  last edited by

                                  @stpq:

                                  and does it violate OSI model to have two interfaces with addresses from the same subnet?

                                  You have two interfaces:  eth0 at 192.168.1.13 and eth1 at 192.168.1.14

                                  Your default gateway is 192.168.1.1

                                  Which interface(s) should be used to send traffic to the gateway?

                                  It's not against the model, but requires special consideration and per-interface (not just per-subnet) routing rules.

                                  Chattanooga, Tennessee, USA
                                  A comprehensive network diagram is worth 10,000 words and 15 conference calls.
                                  DO NOT set a source address/port in a port forward or firewall rule unless you KNOW you need it!
                                  Do Not Chat For Help! NO_WAN_EGRESS(TM)

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                                  • johnpozJ
                                    johnpoz LAYER 8 Global Moderator
                                    last edited by

                                    @stpq:

                                    "So your complaint is your ssh client doesn't reconnect for you?"
                                    yeah, but do u have any clue how long it takes for ssh to timeout?

                                    Would depend on the settings in ssh server.  What are the settings for ClientAliveInterval, TCPKeepAlive and ClientAliveCountMax?  They could be very short, or very long depending on what the admin of the ssh server set.

                                    Where is this a ISC dhcp feature - just because you can get something to load and function in the config, does not mean its a SMART thing to do ;)  You can do lots of things that some software will allow - doesn't mean its good practice ;)

                                    Networking 101, mac's are suppose to be unique.  You wouldn't want the same IP address on different macs..

                                    An intelligent man is sometimes forced to be drunk to spend time with his fools
                                    If you get confused: Listen to the Music Play
                                    Please don't Chat/PM me for help, unless mod related
                                    SG-4860 24.11 | Lab VMs 2.7.2, 24.11

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                                    • C
                                      Cino
                                      last edited by

                                      I agree with what everyone is saying but there is a way to assign the same static IP to two different MACs. I do it if I assign a static IP to a device that has multiple interfaces (WDTV, Roku 3, TVs, Work Laptop)

                                      This is not supported by pfsense and could break your system if you mess up!!! I hold no responsible if you break your system nor do I offer support. But I am willing to share the knowledge of how it can be done

                                      You will have have to manually edit your config.xml… Goto you the <dhcpd>section then look for <staticmap>... You should get the idea of how to do this...Once you save your changes, reboot your box..

                                      
                                      			 <staticmap><mac>00:19:9d:12:9f:4c</mac>
                                      				<ipaddr>192.168.0.51</ipaddr>
                                      				<hostname>vizio</hostname>
                                      
                                      				 <filename><rootpath></rootpath></filename></staticmap> 
                                      			 <staticmap><mac>00:19:9d:08:dc:05</mac>
                                      				<ipaddr>192.168.0.51</ipaddr>
                                      				<hostname>vizio</hostname></staticmap> 
                                      
                                      

                                      Capture.JPG
                                      Capture.JPG_thumb</staticmap></dhcpd>

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