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Description of the problem: In IPv4 addressing a host should not have an address which is: A) subnet ID B) broadcast address The default gateway should be in the same subnet as the host. Otherwise it's unreachable from the host. Example IPv4 class A Subnet ID: 10.0.0.0 Subnet Mask: 255.240.0.0 Mask Bits: 12 Host Address Range: 10.0.0.1 - 10.15.255.254 Broadcast Address: 10.15.255.255 (Note: In this context, IP: 10.10.0.0 is a valid host address. The same is true for 10.10.10.0.) IPv4 class B Subnet ID: 172.16.64.0 Subnet Mask: 255.255.192.0 Mask Bits: 18 Host Address Range: 172.16.64.1 - 172.16.127.254 Broadcast Address: 172.16.127.255 (Note: In this context, IP: 172.16.65.0 is a valid host address. The same is true for 172.16.127.0.) IPv4 class C Subnet ID: 192.168.0.96 Subnet Mask: 255.255.255.240 Mask Bits: 28 Host Address Range: 192.168.0.97 - 192.168.0.110 Broadcast Address: 192.168.0.111 The unreachable gateway Subnet ID: 192.168.0.0 Subnet Mask: 255.255.255.192 Mask Bits: 26 Host Address Range: 192.168.0.1 - 192.168.0.62 Broadcast Address: 192.168.0.63 The default gateway should be in the host address range. The address 192.168.0.254 is outside of the subnet. OS: RHEL Workstation release 7.3 (Maipo) Kernel: kernel-3.10.0-512.el7.x86_64 Version-Release number of selected component (if applicable): network-manager-applet-1.4.0-2.el7.x86_64 nm-connection-editor-1.4.0-2.el7.x86_64 How reproducible: Always Steps to Reproduce: 1. Start nm-connection editor 2. Add a new connection 3. Chose type Ethernet 4. Open tab "IPv4 Settings" 5. Add an IP address which coincides with A) subnet ID IP: 192.168.0.64, netmask: 255.255.255.192, gateway: 192.168.0.126 B) broadcast address IP: 192.168.0.127, netmask: 255.255.255.192, gateway: 192.168.0.126 6. Set a gateway that is outside of the current subnet IP: 172.16.0.1, netmask: 255.255.240.0, gateway: 172.16.16.254 Actual results: The nm-connection-editor accepts the IPv4 address of a host to be a subnet ID or a broadcast address. Expected results: The nm-connection-editor does not allow the IPv4 address of a host to be a subnet ID or a broadcast address. Additional info: An on-line subnet calculator is used for better overview of subnetting: http://www.subnet-calculator.com/
kernel allows both to configure the network address and the broadcast address (for example using `ip addr add`). Why do you think NetworkManager should disallow it?
(In reply to Thomas Haller from comment #1) > kernel allows both to configure the network address and the broadcast > address (for example using `ip addr add`). > > Why do you think NetworkManager should disallow it? Hi Thomas, My job is to test the current functionality of Linux. It is true that I cannot disallow something that is allowed by the kernel. To change the functionality of NetworkManager is for someone who is architect or software developer. I cannot take such a decision from the position of software tester. Hence, I close this request.