After an IP address is assigned to this network interface, with any of the the following commands:ip addr add 10.0.0.0 dev eth1 valid_lft forever preferred_lft foreverip addr replace 10.0.0.0 dev eth1 valid_lft forever preferred_lft foreverip addr add 10.0.0.0 dev eth1ip addr replace 10.0.0.0 dev eth1I can verify with ip addr that the IP address for eth1 is set to 10.0.0.0/32 which is excellent (I think):...3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 1000    link/ether 08:00:27:4d:1e:43 brd ff:ff:ff:ff:ff:ff    inet 10.0.0.0/32 scope global eth1       valid_lft forever preferred_lft forever    inet6 fe80::a00:27ff:fe4d:1e43/64 scope link tentative dadfailed        valid_lft forever preferred_lft forever...I begin to ping myself...the ping command hangs on the 31st ping:username@computer:~$ ping 10.0.0.0PING 10.0.0.0 (10.0.0.0) 56(84) bytes of data.64 bytes from 10.0.0.0: icmp_seq=1 ttl=64 time=0.043 ms64 bytes from 10.0.0.0: icmp_seq=2 ttl=64 time=0.034 ms...64 bytes from 10.0.0.0: icmp_seq=30 ttl=64 time=0.038 ms64 bytes from 10.0.0.0: icmp_seq=31 ttl=64 time=0.041 msOnce the ping hangs, I can verify with ip addr that the IP address for eth1 is has disappeared:...3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN group default qlen 1000    link/ether 08:00:27:4d:1e:43 brd ff:ff:ff:ff:ff:ff    inet6 fe80::a00:27ff:fe4d:1e43/64 scope link tentative dadfailed        valid_lft forever preferred_lft forever...How can one assign a static IP address to a network interface using ip(8), and not let it disappear? (disappearing after system restart is OK)I am running Ubuntu 14.04.From researching on the Internet about my problem, it seems that modifying the file /etc/network/interfaces is the solution, but this is undesirable, because this solution is not as portable as the ip(8) command.
how can one manually assign a permanent / static IP address with ip addr add?
ip;ethernet;ping;portability
Your problem is not ip addr but some process (network manager?) which deletes the IP address. Unfortunately I am not aware of a possibility to determine which process made this access.In case the disturbing process calls ip it should be possible with process accounting (man acct) but not if the configuration is made directly via the NETLINK socket.You may kill or stop suspicious processes to find out which one does that.