wan failover with same PUBLIC IP

[Guest]

[razorjack]

Hi all, sorry if I start with a common problem,
I try to set a failure wan connection with my installation of EFW
have 3 lan port 2 red and 1 green
one of these red is the main connection, second obiously is the backup connection,
ISP when main connection goes down and I start the backup, assign same Public IP that I have in the main connection...
all ok if I do it manually..
but when I set the backup by EFW, setting failover connection, setting the host to test, main uplink try 3 times to connect then switch to backup!
woaa all ok!!
here the problem..
after 2 minutes or 3, EFW Try to establish a new connection with main uplink and close the backup!! and the backup uplink stay down forever...
why?? (only things that I see in log is a strange entry tells "cannot shutdown main uplink" but in home page of EFW it tell failure of the main uplink..)

thanks for you help
I hope there's a solution becouse ISP want 80€ per month for a cisco router to do this!!!

[sourcebreak]

If Gigabit NIC - use CAT 6 patch cable.   my uplink was dead on CAT 5 and changed to UP on CAT 6 patch cable