While carrying out labs on vulnerable machines (e.g., Metasploitable2 and OWASP Juice Shop) it is not advisable to expose them to the internet. But, during setup, you may need internet access to download tools, dependencies, or even clone repositories that will add your lab work, this is where Dual-Homing (the use of dual network interfaces) could come in handy.
Dual-homed or dual-homing can refer to either an Ethernet device that has more than one network interface, for redundancy purposes, or in firewall technology, one of the firewall architectures for implementing preventive security.
Each interface or port is connected to the network, but only one connection is active at a time. The other connection is activated only if the primary connection fails. Traffic is quickly rerouted to the backup connection in the event of link failure.
In my Project Distributed Pentesting Lab Setup, I deployed an Ubuntu VM which I intended to configure as OWASP Juice Shop.
During the setup process, I discovered I had no network access, while this was expected because of the Host-Only network configuration of my vulnerable machines, I could not download the dependencies neither can I clone the juice-shop repository needed to setup OWASP Juice Shop.
This became a challenge for me because I had to find a way to connect the VM to the internet without breaking my lab architecture.
To fix this, I had to add a second network adapter (NAT) to the VM which gave me network access temporarily to download the required tools.
After making use of the internet access, I had to remove the network adapter to maintain isolation and consistency with the lab architecture.
https://en.wikipedia.org/wiki/Dual-homed
https://netseccloud.com/dual-homing-explained-what-is-it-and-how-does-it-work