DHCP Question...



  • This is for a friend of mine who asked me ; And Wanted to be able to send him a link to read up on DHCP Best practices and ideas on his situation.

    He came to me and said "if you set up a dhcp why do you set up .2-.254 with a gate way of .1
    don't you want to keep some open for Static IPs... for example: printers?"

    what can I say to him other than .1 is reserved for gateway? .1 is the gateway so it can't be used in the scenario.

    He is explaining to me that this company Cybera is setting up a firewall for him at his location and is curious why they would leave it that wide and open without any reserved Static IPS.

    I'm sending him the link to this thread to have him read through the answers I get.



  • So, .1 is not reserved. You can put your gateway anywhere in your range. It is simplest, and typical to put it at .1. The reason why organizations do not create space in their DHCP scope for static addresses is that they are managing devices that would have been assigned static addresses in the past, via other means. One way is using DHCP reservations. Another is using a utility or print server so that the end point never needs to know the current IP address of a printer.



  • @JaredBusch posted several years ago about how he does it, and I've adopted it.

    He avoids static whenever possible. There are times where you should absolutely use static (hypervisors/iLo/iDrac, etc).

    But for things like servers and printers - instead of static, used DHCP reservations. This allows you to change IP settings for these devices from the DHCP stack instead of visiting each device and changing them manually.

    You can still use a reservation for a device you set statically as well, just the DHCP server will never hand out that reservation, but you'll have a single list of what is assigned at least to the MAC level.



  • .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png



  • .1 isn't reserved, but it's the practice that's most used .
    Understood.



  • @Kelly said in DHCP Question...:

    Another is using a utility or print server so that the end point never needs to know the current IP address of a printer.

    Have you found this to work? Even on print servers, I print to IP, and the server print queue is static to that IP.
    I haven't used WSD ports on a server yet - have you?



  • @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    yeah, the places I came from used .254 as the gateway - so the whole .1 thing was weird for me.... but .1 is seen by all consumer gear today, and likely most commercial as well.



  • Yep I agree with others. Just don't use static IPs at all. If you don't have to use reservations that's even better.



  • @Dashrender said in DHCP Question...:

    @Kelly said in DHCP Question...:

    Another is using a utility or print server so that the end point never needs to know the current IP address of a printer.

    Have you found this to work? Even on print servers, I print to IP, and the server print queue is static to that IP.
    I haven't used WSD ports on a server yet - have you?

    I haven't tbh. I know about it, but it wasn't worth the investment to implement in prior environments. Now I have nothing to do with it.



  • @IRJ said in DHCP Question...:

    Yep I agree with others. Just don't use static IPs at all. If you don't have to use reservations that's even better.

    It's likely best to use DNS names when possible, because - who cares what the IP address is?



  • @Dashrender said in DHCP Question...:

    @IRJ said in DHCP Question...:

    Yep I agree with others. Just don't use static IPs at all. If you don't have to use reservations that's even better.

    It's likely best to use DNS names when possible, because - who cares what the IP address is?

    Yes and it makes restoring servers and services so much easier. It's nearly a must have for good DR.



  • @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?



  • @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.



  • @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information



  • @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.



  • @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.

    At least his response was helpful. Taking a screenshot of you having gateway to .50 isn't a convincing argument.



  • @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.

    @Kelly made an intelligent response and

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.

    At least his response was helpful. Taking a screenshot of you having gateway to .50 isn't a convincing argument.

    How is it not convincing? It's empirical proof that .1 isn't reserved for the purported purpose.



  • Take your arguing BS somewhere else ; keep it off my thread.



  • @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.

    @Kelly made an intelligent response and

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    @IRJ said in DHCP Question...:

    @DustinB3403 said in DHCP Question...:

    .1 isn't reserved, it's just a practice that people keep using.

    m8DrFMhQDh.png

    Do you just reply to threads because you are bored?

    I've only replied to this thread. I'm not sure what you're on about.

    With zero relevant information

    Gent Bent?

    He asked stated .1 as being reserved. I proved it wasn't. I can't help it that @Kelly responded faster than I did.

    At least his response was helpful. Taking a screenshot of you having gateway to .50 isn't a convincing argument.

    How is it not convincing? It's empirical proof that .1 isn't reserved for the purported purpose.

    If Dustin has a screenshot it must be undeniable evidence of something.



  • @WrCombs said in DHCP Question...:

    Take your arguing BS somewhere else ; keep it off my thread.

    You had your question answered. So whats the issue?



  • @IRJ said in DHCP Question...:

    @WrCombs said in DHCP Question...:

    Take your arguing BS somewhere else ; keep it off my thread.

    You had your question answered. So whats the issue?

    That's my Point: It's been answered, I don't want/nor need to see you guys Arguing about what ever the hell is it Dustin did or didn't do, or what your issue is with his replies.



  • @WrCombs said in DHCP Question...:

    He is explaining to me that this company Cybera is setting up a firewall for him at his location and is curious why they would leave it that wide and open without any reserved Static IPS.

    If this company is setting up a firewall for him, at the firewall there may not be any additional available IPs to be publicly used. IE the site may only have 1 static IP address provided by the ISP.

    It's unusual that they wouldn't have more than just the 1 IP address, but it's possible that their network is just packed. Do you know if he is being given an IPv4 or IPv6 public address for the firewall?

    As for internally, usually, you'd want to set your address pool to cover the expected usable devices, rather than just wide open .1-254.

    You might have DHCP pool from .100-254 if you don't have a large number of devices and then anything from 1-50 could be a reservation.

    Obviously something within the range needs to be the gateway so you'd take one address for that. (presumably from outside of the pool).



  • @DustinB3403 said in DHCP Question...:

    @WrCombs said in DHCP Question...:

    He is explaining to me that this company Cybera is setting up a firewall for him at his location and is curious why they would leave it that wide and open without any reserved Static IPS.

    If this company is setting up a firewall for him, at the firewall there may not be any additional available IPs to be publicly used. IE the site may only have 1 static IP address provided by the ISP.

    It's unusual that they wouldn't have more than just the 1 IP address, but it's possible that their network is just packed. Do you know if he is being given an IPv4 or IPv6 public address for the firewall?

    As for internally, usually, you'd want to set your address pool to cover the expected usable devices, rather than just wide open .1-254.

    You might have DHCP pool from .100-254 if you don't have a large number of devices and then anything from 1-50 could be a reservation.

    Obviously something within the range needs to be the gateway so you'd take one address for that. (presumably from outside of the pool).

    The point is that everything in that subnet should be in the DHCP pool. Make a reservation if you need it



  • @WrCombs said in DHCP Question...:

    .1 isn't reserved, but it's the practice that's most used .
    Understood.

    More clearly, the top or bottom of the subnet is usually the gateway, because it stays out of the way of anything else that may be desired to be put on the subnet.

    A typical 192.168.1.0/24 means that your usable IP range is 192.168.1.0 through 192.168.1.254.

    If you then want to keep things in certain ranges, having the gateway in the middle of nowhere is just annoying.

    So people choose either .1 or .254.
    Say you decide to use .1, then you will look at your network and say that I want .2 through .100 to be my networking stuff.
    Then .101 through .254 to be the general DHCP pool for all the junk.

    How you "block" this all off depends on your DHCP server.
    How you use DHCP reservations will also depend.

    I don't have to time show you some competing screenshots of the process.



  • @JaredBusch said in DHCP Question...:

    @WrCombs said in DHCP Question...:

    .1 isn't reserved, but it's the practice that's most used .
    Understood.

    More clearly, the top or bottom of the subnet is usually the gateway, because it stays out of the way of anything else that may be desired to be put on the subnet.

    A typical 192.168.1.0/24 means that your usable IP range is 192.168.1.0 through 192.168.1.254.

    If you then want to keep things in certain ranges, having the gateway in the middle of nowhere is just annoying.

    So people choose either .1 or .254.
    Say you decide to use .1, then you will look at your network and say that I want .2 through .100 to be my networking stuff.
    Then .101 through .254 to be the general DHCP pool for all the junk.

    How you "block" this all off depends on your DHCP server.
    How you use DHCP reservations will also depend.

    I don't have to time show you some competing screenshots of the process.

    Think I have a better understanding of it now.
    Thanks



  • @WrCombs said in DHCP Question...:

    He came to me and said "if you set up a dhcp why do you set up .2-.254 with a gate way of .1
    don't you want to keep some open for Static IPs... for example: printers?"

    Because you don't actually need statics. DHCP can have pre-assigned, so there is never a need for a static address other than for the gateway and the DHCP server itself. Just not necessary.

    Static are a fine option, but only an option. There's no need for it.



  • @WrCombs said in DHCP Question...:

    He is explaining to me that this company Cybera is setting up a firewall for him at his location and is curious why they would leave it that wide and open without any reserved Static IPS.

    Simply not needed. He's imaging that statics do something that they do not. It's common to use statics, and nothing wrong with it. but it is generally considered "less ideal" to do so.



  • @Dashrender said in DHCP Question...:

    He avoids static whenever possible. There are times where you should absolutely use static (hypervisors/iLo/iDrac, etc).

    What would make those absolutely static? As long as you have DHCP working, they don't need to be static. When do you want or need any of them during a DHCP outage? DHCP can be fixed in minutes even when HA has failed.

    There is no "absolutely need" statics outside of the gateway and DHCP server.



  • @WrCombs said in DHCP Question...:

    .1 isn't reserved, but it's the practice that's most used .
    Understood.

    Reserved "in our minds" 🙂 But not reserved in DHCP terms.



  • @IRJ said in DHCP Question...:

    Yep I agree with others. Just don't use static IPs at all. If you don't have to use reservations that's even better.

    Even that is getting more and more rare, for sure.