SOLVED reconfigure ethernet ports and IP addresses AFTER fog is installed and configured

  • I need to reconfigure ip addresses on my FOG Server. I currently have eno1 configured for management on my LAN and eno2 for imaging/dhcp. both addresses begin with 10 and they both have the same netmask. i cant connect to the server from my LAN, but can from the isolated network on eno2. If i disconnect the cable from eno2, use netplan to apply or just reboot, then plug the cable back into eno2, then i can connect from my LAN. The problem comes back though. So im wondering if there is a way and how to reconfig the interfaces and fog to be as such: DHCP/Imaging on eno1 with a 172 address and a smaller mask, and eno2 to be the management interface for LAN.

  • you da man!

  • Moderator

    @brakcounty Then what you should have now is a typical setup for having a business network and an isolated imaging network. FOG will work in this configuration no problem as well as you will be able to update fog in the future without making any changes to the network configuration.

  • i removed the gateway from eno2 and tested pxe boot successfully. i forgot that the gateway isnt needed if the clients dont need to get passed the server.

  • Moderator

    @brakcounty If we look at this as just a pure routing issue I would wonder why on the en02 network you have a default router (route) defined of (eno2 IP address). I don’t see what Linux OS you are using, but I would surely look into your network settings for eno2 and remove any gateway value on that interface. You should only have a gateway defined on eno1 so that eventually the FOG server can reach the internet for updates and installation. Typically an imaging network consists of only one subnet so you don’t define a gateway value for the imaging network.

  • I use eno2 for imaging/DHCP and eno1 for management from my LAN
    Screenshot from 2019-10-17 15-10-03.png

  • Moderator

    @brakcounty Lets find out a bit more about your setup run these commands and capture the output.

    ip addr show
    ip route show

    Which address is for your imaging network and which address if for the management network. You have 2 default routes showing, not generally a good idea.

  • Here is my routing table:

    I am wondering if i should just change the netmask on eno2 to Does that sound like a good idea?

  • @brakcounty Having two network interfaces configured for the same subnet (found by performing an AND with the interface’s IP address and subnet mask) but not having those interfaces actually connected to a common network is going to cause problems. When sending traffic to an IP address, a routing table is consulted to direct the traffic to the appropriate interface. If there is no differentiation between the interfaces, then you are depending on the order in which the routing table was built to determine to which interface outbound traffic is sent. As there are a number of things that could trigger a change to that table, such as media disconnects, reboots, and dhcp lease expirations (if your fog server is not configured to use static addresses), access to the machine through both interfaces will be unpredictable. You should change your network configuration so that the interfaces are in different networks.

  • so now all of a sudden i can access the FOG Server from the management/LAN interface.

  • I don’t believe that process has changed since 1.3 (someone please correct me if I am off on this), but the Wiki article for changing a server IP Address points to making those changes in /opt/fog/.fogsettings and re-running the installer to take care of the FOG configuration. Changing the IP address for the OS will be dependent on distribution. Which flavor are you running?