How to configure two NIC

Dear all
I have vpn server with two NIC the first one connected with modem
For Ex:-
78.93.40.100 assign to the modem
78.93.40.101 assign to the first NIC
The second NIC connected with local network and take automatically IP from anther modem
For EX: – 192.168.1.117
The problem I can’t login to the server using remote connection and I can’t make ping to 78.93.40.101
Until login locally and make repair for the first NIC the problem happened each 10 minute