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
 


  • Linux How To Clone One System Harddrive to another remote system
  • Ubuntu/Debian/Linux won't boot and drops to Busybox shell after cloning HDD with dd
  • Unable to negotiate with 192.168.1.99 port 22: no matching host key type found. Their offer: ssh-dss Solution
  • Centos 7 Password Reset
  • MySQL Adding New Field to Existing Database Table
  • MySQL Cannot Update/Write to any database table solution
  • Centos How To Update to Glibc 2.14 Plus
  • php remove last letters of string
  • MySQL Maximum INT Size Truncation Issue/Warning
  • MySQL How To Add New Field Column To Existing Table
  • mysql how to reset passwords with a few commands
  • htaccess apache how deny/allow to block or allow by IP address
  • PHP geoip.so fatal error Solution
  • Syntax error on line 221 of /etc/httpd/conf/httpd.conf: Syntax error on line 6 of /etc/httpd/conf.d/php.conf: Cannot load /etc/httpd/modules/libphp5.so into server: /etc/httpd/modules/libphp5.so: cannot open shared object file: No such file or direct
  • GCC 5 on Centos 6 - How To Install
  • bash find line and replace howto
  • How To Create Apache htpasswd file
  • possible SYN flooding on ctid 42131, port 80. Sending cookies. - Solution
  • Linux last command show login by IP instead of hostname
  • Install Windows From a Linux TFTP Server instead of using WDS Solution