Linux Mint/Ubuntu/Debian Dual NICs networks problem when enabling and disabling one device -

Linux Mint/Ubuntu/Debian Dual NICs networks problem when enabling and disabling one device

The Scenario

You have dual NICs and you disable NIC1 which uses 192.168.1.1 as its gateway.  With NIC2 you enable it/connect it to another network which also has the gateway 192.168.1.1

Everything will work fine at this point.

When switching back to NIC1 even with NIC2 disabled and even unplugged, the OS basically can't pick up the new/updated ARP entry of the old device for 192.168.1.1 and perhaps thinks it is a security risk or spoof of some sorts and blocks it all.  You may think there is an issue somewhere else but the syslog shows the issue below.

Mar 13 23:16:58 mybox dbus[1698]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.9" (uid=0 pid=2031 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.6" (uid=0 pid=1983 comm="NetworkManager ")
Mar 13 23:16:59 mybox dbus[1698]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.9" (uid=0 pid=2031 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.6" (uid=0 pid=1983 comm="NetworkManager ")
Mar 13 23:17:01 mybox CRON[27807]: pam_unix(cron:session): session opened for user root by (uid=0)
Mar 13 23:17:01 mybox CRON[27807]: pam_unix(cron:session): session closed for user root
Mar 13 23:17:16 mybox sudo: pam_unix(sudo:auth): conversation failed
Mar 13 23:17:16 mybox sudo: pam_unix(sudo:auth): auth could not identify password for [one]
Mar 13 23:17:24 mybox smbd[21006]: pam_unix(samba:session): session closed for user nobody
Mar 13 23:17:41 mybox dbus[1698]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.9" (uid=0 pid=2031 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.6" (uid=0 pid=1983 comm="NetworkManager ")
Mar 13 23:17:42 mybox dbus[1698]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.9" (uid=0 pid=2031 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.6" (uid=0 pid=1983 comm="NetworkManager ")

Solution

 sudo service network-manager restart
network-manager stop/waiting
network-manager start/running, process 31647
 


  • /usr/bin/ld: cannot find -lboost_system-mt-s /usr/bin/ld: cannot find -lboost_filesystem-mt-s /usr/bin/ld: cannot find -lboost_program_options-mt-s /usr/bin/ld: cannot find -lboost_thread-mt-s collect2: error: ld returned 1 exit status make: *** [cag
  • Wine uninstalled broken on Linux Mint
  • ffmpeg trouble concatenating similar but different files
  • ffmpeg Unable to Use Hardware Encoding with Nvidia 3.40 Driver and GT210 card
  • Linux Mint USB Kernel Tainted and Locked Port/Dev File
  • ffmpeg Linux Mint download, compile and install howto
  • OpenVZ error : Container start failed (try to check kernel messages, e.g. "dmesg | tail") Locked by: pid 166638, cmdline vzctl start 888171
  • How to extract view contents of initramfs image gzip'd
  • Linux how to copy GPT partition table with dd
  • Centos 7 How To Change Hostname
  • Debian/Mint/Ubuntu Font Packs/Recommended To Install
  • Migrate Centos 7 from Single HDD to mdadm RAID 10 array:
  • How to change reserved blocks in Linux partition
  • Reading package lists... Done W: GPG error: http://ppa.launchpad.net trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D46F45428842CE5E
  • Centos 7 A start job is running for dev-mapper-clx2droot.device (8min 44s / no limit)
  • USB 3.0 External HDD Enclosure Seagate UAS problems - [sdd] tag#1 CDB: Write(16) 8a 00 00 00 00 01 70 04 08 68 00 00 00 08 00 00
  • Centos 7 Cudaminer Nvidia setup guide
  • USB 3.0 PCI x1 Card Review VIA VL805 on Linux Review and Experience
  • rsync run as root sudo without password
  • Why won't my Linux Mint boot after I manually installed a new kernel?