Using a Static IP Address on a Raspberry Pi Connected to my Nighthawk Router

antinode
Guru
Jun 29, 2020
> I have a couple of Raspberry Pis [...]

   Model? Network interfaces? Raspbian?

> [...] I want to set up a static IP Address for each of these Pis,
> [...]

   Why?

   Terminology: A "static" address is configured on the device itself.
What you configure on a (DHCP server on a) router is a reserved dynamic
address, not a static address. Which do you mean?

   Do you really care which way you get a fixed address? Using static
addresses requires more care in the configuration of the DHCP server.
(See below.)

> [...] This works, but it means that I can only have the IP Address
> that the Router gave me through DHCP before I reserved it. [...]

   It _does_? How did you arrive at that conclusion?

> [...] What I really want is to specify static IP Addresses in the
> 'dhcpcd.conf' file on the Pis and have the Router accept these as the
> addresses to use.

   Is that what you "really want", or is it what you believe is the only
way to get what you _really_ "really want", namely free choice of fixed
IP configuration for these gizmos? Don't choose the solution before you
define the problem.

> Also. If I reserve the DHCP Server on the Router gave me, I'm sure I
> used to be able to edit this to the IP Address that I want but this also
> causes the system to fail. [...]

   Huh? "reserve the DHCP Server"? Does that mess make sense to you
when you read it?

   If you do enough playing with address reservations, then you might
need to shut down the router (DHCP server) and all the client devices,
and then restart everyone to get everyone into a consistent condition.

> Configure the Raspberry Pi staticly. [...]

   I typically wouldn't. I usually don't. I usually use address
reservation for mine (Zero W, 3 B+), and it works just fine (on a
D7000[v1], V1.0.1.78_1.0.1).

   But, if you want to specify odd-ball parameters, like, say, a DNS
server other than the router, then DHCP from the router would not do
what you want.

> What do you mean by 'mask and gateway' in this context?

   The "subnet mask" is specified by your "/24". "/24" is equivalent to
"255.255.255.0" (that is, 24 binary ones). (And it's more compact.)
"ifconfig" uses the old (bulky) notation in its reports.

   "[default] gateway" and "default router" are equivalent.

   If you decide to use static addresses, then you should shrink the
DHCP pool on your router (DHCP server) from its default range,
".2" - ".254", to something smaller, like, say, ".100" - ".254". Then
use the available non-pool addresses (".2" - ".99") as your static
addreses. That way, you don't need to worry about the DHCP server
granting your static addresses to some DHCP clients.

   Around here, on an R-Pi Zero W (so the network interface is "wlan0"),
I set the following in "/etc/dhcpcd.conf":

interface wlan0
static ip_address=10.0.0.150/24
static routers=10.0.0.1
static domain_name_servers=10.0.0.140

(I wouldn't bet that setting "static domain_name_servers" there has any
effect on name resolution. "/etc/resolvconf.conf" might have more
influence over that than anything in "/etc/dhcpcd.conf".)

   My subnet is different ("10.0.0.*" rather than "192.168.1.*"), but
otherwise we seem to be doing similar things. Mine works:

pi@rpizw:~$ ping -c 1 dns.google
PING dns.google (8.8.8.8) 56(84) bytes of data.
64 bytes from dns.google (8.8.8.8): icmp_seq=1 ttl=118 time=67.7 ms
--- dns.google ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 67.708/67.708/67.708/0.000 ms

> Model: D7800|Nighthawk X4S - AC2600 WiFi VDSL/ADSL Modem Router

   Is that accurate? Wouldn't a D7800 default to "192.168.0.*", not
"192.168.1.*"? Are you just configuring the R-Pi on a wrong subnet?
- TerryJColes
  Luminary
  Jun 30, 2020
  The reason I am doing all this is because I am stuck at home in shielding and we have an extensive private network at our local Model Town which is used to control around 20 Pi based devices which measure water levels, operate pumps and open valves in the model river system. Owing to lockdown we are unable to get to the site to monitor this or take readings.
  
  The two Raspberry Pis in question are both Pi3s but the remaining Pis are all Zeros. One of the Pi3s has been in place for three years and is running a Captive Portal and Webserver. This needs two Ethernet ports; eth0 connected to the Pis network on 192.168.0.* and eth1 connected to the Model Town's Office Router on 192.168.1.*, (Yes that is the IP Range of my Nighthawk. I set it that way because that is the IP Range of the Office Router and the Pis subnet was the same as the Nighthawk subnet.)
  
  To get round the problems of lockdown (Most of us are in shielding) we are installing a VPN Server which I am testing at home using a subset of the Model Town's hardware. I want static IP Addresses for the Webserver and VPN Server because the VPN Server needs both ports to be static and the Webserver is easier to test while I am developing the system here at home.
  - antinode
    Guru
    Jun 30, 2020
    > [...] One of the Pi3s has been in place for three years and is running
    > a Captive Portal and Webserver. [...]
    
       I don't know what "Captive Portal" means to you, but I may not need
    to.
    
    > [...] This needs two Ethernet ports; eth0 connected to the Pis network
    > [...]
    
       You lost me. To make sense of this, I'd need a map showing what's
    connected to what, including which IP addresses are used on which LAN
    segments. So far, I'm not even sure how many routers you have. Or
    where the Internet connection appears.
    
    > [...] we are installing a VPN Server [...]
    
       I know nothing about that, either. (Or VPNs, in general, for that
    matter.)
    
       The one piece of "/etc/dhcpcd.conf" which you exhibited looked ok to
    me. If you're having trouble getting to the Internet that way, then I'd
    worry more about the router configuration and the routes on the R-Pi
    than on its basic IP configuration. Possibly interesting:
    
          ifconfig
          netstat -rn
    
          Typically, if you're using multiple subnets, then someone needs more
    routing info than a simple default route/gateway. Your main router, for
    example.
    
    > [...] AFAIK the subnet mask is defined by the /24 in the declaration.
    
       Yes, as I said.
TerryJColes
Luminary
Jun 30, 2020
labatt wrote:
> I suspect when you did the actual configuration on the Pi you were asked mask. That does not show when doing the command you gave.
I don't understand what you mean by 'asked mask'? This is not done by some kind of wizard. It is done by editing the file dhcpcd.conf. AFAIK the subnet mask is defined by the /24 in the declaration.

Forum Discussion

Using a Static IP Address on a Raspberry Pi Connected to my Nighthawk Router