Does a NAT Virtual Machine Inherit the Host’s Proxy Login?
Identify whether a guest shares an IP-based network authorization or actually authenticates to an explicit proxy.
A guest browsing after the host logs in does not show that NAT passed the host's proxy password to the guest. Two mechanisms can look similar:
| Mechanism | What gets authorized |
|---|---|
| Explicit HTTP proxy authentication | A proxy challenge, such as 407, is answered with credentials under the proxy's rules |
| Address-based portal or network access grant | Traffic associated with a visible source address |
With NAT, host and guest traffic can share the host's translated source. A grant keyed only to that address can therefore cover both. NAT itself neither copies browser proxy settings nor generates Proxy-Authorization for guest applications.
To distinguish them, identify whether the guest connects to an explicit proxy or goes directly through the gateway. Then determine whether upstream policy authorizes a user, connection, device or address. If the guest does use a proxy, inspect its rules and any existing authenticated-connection behavior; no prompt alone cannot identify the method.
A bridged guest can present a different source and encounter the portal again. IPv6 can also take another path from IPv4 NAT. For individual accountability, choose an identity boundary that distinguishes the required users rather than assuming one translated address represents one person.