For a BGP session to reach the Established state, the peers must agree on the AS numbers. If the local device is configured with a local AS that does not match what the remote peer expects as its neighbor’s AS, the session will cycle through Active/Connect states but never establish. While hold-time mismatches are common, BGP will negotiate to the lower value; the session would still establish. Both ends being passive would prevent connection initiation but is a less common real-world scenario than a simple AS mismatch.

By default, Junos BGP only advertises routes that are active (installed as the selected route) in the routing table. OSPF internal routes might be present in the OSPF routing table (ospf.0) but if they are not the best route to the destination (e.g., a direct or static route is preferred), they are inactive in inet.0. The ‘advertise-inactive’ configuration under BGP allows the protocol to advertise routes learned from other protocols even if they are not the active best path.

Juniper Junos uses a per-flow load-balancing algorithm by default for unicast IP traffic, which is the standard and desired behavior to prevent packet reordering. True per-packet load balancing, where each packet is sent to a different next-hop in a round-robin fashion, is not supported for general unicast routing in Junos. It is supported in specific scenarios like multicast (per-packet reverse-path forwarding) or on certain MX Series platforms with special configurations for legacy support, but it is not a standard feature for the JN0-363 scope.

Effective load distribution in an AE bundle relies on the hashing algorithm and the diversity of traffic flows. The hashing algorithm (e.g., source/destination IP, source/destination port, MAC) determines which bits of the packet header are used to select a member link. If all traffic flows have identical source/destination pairs (e.g., a single large data transfer), the hash will always point to the same member link, causing imbalance. The LACP priority affects which end is the actor and negotiates the bundle but doesn’t directly impact the hashing and distribution of traffic once the bundle is formed.

The ‘show firewall’ command is the primary tool for viewing statistics related to configured firewall filters and policers. When you use ‘then count’ in a filter term, a counter is created for that term. Executing ‘show firewall filter ‘ will display the counter names and their current packet/byte counts, allowing you to verify if traffic is matching the term as expected.

An OSPF import policy applied locally on Router A allows you to manipulate the metric (or other attributes) of routes as they are being installed into Router A’s local routing table. By increasing the metric for the specific prefix learned from Router C, you can make the path via Router B (which retains its original, lower metric) the preferred path. This change is local to Router A and does not affect the Link-State Advertisements (LSAs) or the shortest path calculations on any other router in the area.

On a Juniper device, a physical Ethernet interface by default expects Layer 2 framing (like Ethernet with 802.1Q tags). To use it as a simple Layer 3 routed interface (a ‘access port’ in switching terms), you must configure how it handles VLAN tags. The most common method is to set ‘unit 0’ with ‘family inet’ and a ‘vlan-id’ (e.g., 0 for untagged, or a specific number). Alternatively, for a pure L3 interface with no VLAN concern, you can use ‘encapsulation ethernet-bridge’ on some platforms, but the requirement to define the encapsulation/vlan handling is key.

The ‘show route protocol bgp’ command shows all routes learned via BGP, regardless of whether they are active (installed) in the main routing table. The ‘show route’ command shows only the active best-path routes. If a BGP route is learned but not active, it’s often because another route from a different protocol (e.g., OSPF with AD 10, static with AD 5) to the same prefix is already installed. Junos uses Administrative Distance (preference) to choose between identical prefixes from different protocols, and a lower value is preferred. BGP has a default preference of 170, which is higher than OSPF (10) or direct (0).

The proxy-id defines the traffic selectors for the IPSec Security Association (SA). For Phase 2 to establish, the peers must agree on which traffic to protect. On Junos, the proxy-id is defined as a local and remote address pair (which can be networks). For the negotiation to succeed, the ‘local’ address on Peer A must match the ‘remote’ address on Peer B, and vice-versa. Essentially, the values are mirrored or swapped between the two peers. A common configuration error is setting the same local/remote values on both ends, which causes a mismatch and Phase 2 failure.

For a BGP session to reach the Established state, the peers must agree on the AS numbers. If the local device is configured with a local AS that does not match what the remote peer expects as its neighbor’s AS, the session will cycle through Active/Connect states but never establish. While hold-time mismatches are common, BGP will negotiate to the lower value; the session would still establish. Both ends being passive would prevent connection initiation but is a less common real-world scenario than a simple AS mismatch.0