When configuring aloopback interface as the BGP sourceforconnecting to an ISP, two important settings must be applied:

1.Enable EBGP Multihop (ebgp-enforce-multihop)

BGP normally expects directly connected neighbors, but since the ISP and FortiGate A are usingloopback interfaces,packets will not be sent directly between their physical interfaces.

Theebgp-enforce-multihopcommandallows BGP to form an eBGP peering over multiple hops.

2.Set the Update Source (update-source)

Since FortiGate is using aloopback interface as the source, theupdate-sourcecommand ensures thatBGP updates originate from the loopback interfacerather than a physical interface.

This is essential becauseBGP peers must match the source IP with the configured neighbor address.

FortiGate, like other security appliances, cannot analyze encrypted HTTPS traffic unless itdecryptsit first. Ifonly certificate inspectionis enabled, FortiGate can see the certificate details (such as the domain and issuer) butcannot inspect the actual web content.

To fully analyze the traffic and detect potential malware threats:

●Full SSL inspection (Deep Packet Inspection)must be enabled in theSSL/SSH Inspection Profile.

● This allows FortiGate todecrypt the HTTPS traffic, inspect the content, and then re-encrypt it before forwarding it to the user.

● Without full SSL inspection, threats embedded in encrypted traffic may go undetected.

neighbor-group:

● This command is used to group multipleBGP neighborswith the same configuration, reducing redundant configuration.

● Instead of defining individual BGP settings for each spoke, the administrator can create aneighbor-groupand apply the same policies, reducing manual work.

neighbor-range:

● This command allows the configuration ofa range of neighbor IPs dynamically, reducing the need to manually define each spoke neighbor.

● It automatically addsBGP neighborsthat match a given prefix, simplifying deployment.