What is a jump host (bastion host) in network architecture, and what security problem does it solve for accessing servers in a protected network segment?

• A.A jump host is a hardened, single-purpose server at the boundary between a trusted administrative network and a protected server segment - administrators SSH or RDP to the jump host first, then from the jump host to target servers; this centralizes and audits all administrative access through one choke point, minimizing the attack surface of protected servers by preventing direct access from workstations
• B.A jump host is a server that translates SSH protocol to Telnet for legacy server administration, allowing modern admin tools to manage older servers
• C.A jump host is a VPN concentrator that terminates remote-access VPN sessions from administrators connecting from home networks; an IPS must be deployed on a SPAN port to block traffic inline. Layer 7 load balancers cannot terminate TLS, which only Layer 4 devices decrypt. A media gateway converts between copper Ethernet and HDMI for AV networks. SFP transceivers convert optical signals to Wi-Fi for last-meter delivery