SNAT cannot work until reboot

[Guest]

[MattHo]

Hi All,

Main uplink IP: 10.1.1.1
And added additional IP 10.1.1.2
Green zone : 192.168.1.x
Orange zone : 10.168.1.x

I set all outgoing mail from port 25 on orange will be will be SNAT to 10.1.1.2. After the setting, I need reboot for active the rule, but a day later it will be force back to use 10.1.1.1 as the out going IP.

Can anyone help?
Many thanks.

Matt