Outbound IPs for mail and navigation traffic

Hello Kevin,

Really, thanks a lot for your attention.

Yes, my F5 is facing the Internet for inbound connections and it is the default path out of my network to the Internet. I have three ISPs, so I have to load balance inbound and outbound connections across them. The pool of public IPs I mentioned are a set of three IPs, one IP for each ISP. I have four VLANs (three external for the ISPs and one internal for the firewall), but I connected just two physical interfaces of my F5. One interface, which contains three VLANs regarding to the ISPs, is connected to the Internet switch. The other interface, which is managing the internal VLAN, is connected to the firewall. There is just one mail server which is located behind the firewall. Indeed, my F5 must load balance the incoming mail across the three ISPs, but it must not change the source IP due to the firewall is performing spam checking.

Is there any chance to use the same IP pool to load balance incoming and outgoing mail traffic besides applying SNAT outbound? I was provided just three IPs to load balance mail traffic.

I suppose I can apply what you say in the last paragraph. But I have just one internal VLAN. It is better to have two? In this case, does it assure that any user would be given a load balanced public IP to navigate?

Thanks in advance for your response. Really, I appreciate it.

I remain attentive

Best Regards,

Omar