{{tag>network troubleshooting ipv4 ipv6}} ====== network troubleshooting ====== ===== RTNETLINK answers: Cannot assign requested address ===== If it happens when trying to remove de ip address e.g ip addr del 2a01:xxxx:xxxx:xxxx::2 dev enp35s0 try specifying the subnet mask like so ip addr del 2a01:xxxx:xxxx:xxxx::2/64 dev enp35s0 ===== Wired ethernet turns off and on constantly ===== dmesg log: ~$ sudo dmesg -H -w ... [pro15 19:12] RTL8226B_RTL8221B 2.5Gbps PHY r8169-0-2a00:00: Downshift occurred from negotiated speed 100Mbps to actual speed 10Mbps, check cabling! [ +0,000012] r8169 0000:2a:00.0 enp42s0: Link is Up - 10Mbps/Full (downshifted) - flow control off [ +2,048824] r8169 0000:2a:00.0 enp42s0: Link is Down [ +8,959020] RTL8226B_RTL8221B 2.5Gbps PHY r8169-0-2a00:00: Downshift occurred from negotiated speed 100Mbps to actual speed 10Mbps, check cabling! [ +0,000014] r8169 0000:2a:00.0 enp42s0: Link is Up - 10Mbps/Full (downshifted) - flow control off [ +0,163394] r8169 0000:2a:00.0 enp42s0: Link is Down [ +1,240247] audit: type=1107 audit(1702663934.240:136): pid=1078 uid=103 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call" bus="system" path="/org/freedesktop/timedate1" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.113" pid=2106 label="snap.firefox.firefox" peer_pid=5540 peer_label="unconfined" exe="/usr/bin/dbus-daemon" sauid=103 hostname=? addr=? terminal=?' [ +7,588296] RTL8226B_RTL8221B 2.5Gbps PHY r8169-0-2a00:00: Downshift occurred from negotiated speed 100Mbps to actual speed 10Mbps, check cabling! [ +0,000013] r8169 0000:2a:00.0 enp42s0: Link is Up - 10Mbps/Full (downshifted) - flow control off [ +1,259109] r8169 0000:2a:00.0 enp42s0: Link is Down [ +8,866622] RTL8226B_RTL8221B 2.5Gbps PHY r8169-0-2a00:00: Downshift occurred from negotiated speed 100Mbps to actual speed 10Mbps, check cabling! [ +0,000013] r8169 0000:2a:00.0 enp42s0: Link is Up - 10Mbps/Full (downshifted) - flow control off [ +0,047328] r8169 0000:2a:00.0 enp42s0: Link is Down [ +8,784982] RTL8226B_RTL8221B 2.5Gbps PHY r8169-0-2a00:00: Downshift occurred from negotiated speed 100Mbps to actual speed 10Mbps, check cabling! [ +0,000012] r8169 0000:2a:00.0 enp42s0: Link is Up - 10Mbps/Full (downshifted) - flow control off [ +0,214446] r8169 0000:2a:00.0 enp42s0: Link is Down [ +11,364429] r8169 0000:04:00.0 enp4s0: Link is Up - 100Mbps/Full - flow control off [ +0,000016] IPv6: ADDRCONF(NETDEV_CHANGE): enp4s0: link becomes ready [ +0,500115] r8169 0000:04:00.0 enp4s0: Link is Down ... Check the cabling. Plug/unplug the cables from the router and other devices. After this the problem was resolved. ===== ping: google.com: Name or service not known ===== Check your ''/etc/resolv.conf'' if your distro is using that. On Ubuntu systemd-resolvd manages that file, so check systemd-resolvd service. If that seems fine, then it might a symptom of the below problem. ===== connect: Network is unreachable ===== Happens when pinging an IP address. Most likely an issue with a missing route. Check with ''ip r'' and add the route. Here's an example of missing route on a VM server with assigned IPs to the //eth0// interface already. # ip a 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 02:00:00:12:14:7c brd ff:ff:ff:ff:ff:ff inet 198.50.177.218/32 brd 198.50.177.218 scope global eth0 valid_lft forever preferred_lft forever inet6 2607:5300:203:1735:198:50:177:218/64 scope global valid_lft forever preferred_lft forever inet6 fe80::ff:fe12:147c/64 scope link valid_lft forever preferred_lft forever ... # ip r 10.0.1.0/24 dev tun1 proto kernel scope link src 10.0.1.79 169.254.0.0/16 dev eth0 scope link metric 1002 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 ... # ip -6 r unreachable ::/96 dev lo metric 1024 error -113 pref medium unreachable ::ffff:0.0.0.0/96 dev lo metric 1024 error -113 pref medium ... default via 2607:5300:203:1735:: dev eth0 metric 1 pref medium default via 2607:5300:203:1735:: dev eth0 metric 1024 pref medium ... [root@xor1 NetworkManager]# ip r In above output ipv4 is missing a default route, and ipv6 is ok. To fix this case you would run: # ip route add 66.70.179.0/24 dev eth0 src 198.50.177.218 # ip route add default via 66.70.179.53 # ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=113 time=1.31 ms ... You have to know the gateway IP, 66.70.179.53 above, then add a direct route to that because any gateway must be reachable directly on connected interfaces. This gateway IP is actually a bridge ''br0'' interface on the VM host and that's serving as the interface for all of the VMs there. ====== See also ====== * [[wiki:ubuntu_troubleshooting|Ubuntu troubleshooting]] * [[add_additional_ip_address_interface|Add additional ip address on interface]] ====== References ====== * https://superuser.com/questions/1219289/im-unable-to-create-a-static-ip-route-error-says-rtnetlink-answers-network-i