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This option proposes: Inspect the summarization boundary, contributing active component prefixes, aggregate advertisement and forwarding toward the actual destinations. It addresses the different topic OSPF summarization at ABR and ASBR, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

This option proposes: Inspect ingress interface VPN instance, per-instance routes, next-hop resolution and authorized route import or interconnect rules. It addresses the different topic VRF traffic separation and route leaking controls, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

This option proposes: Inspect the user or TACACS/RADIUS identity, assigned privilege, SSH negotiation, source address controls and accounting records for a test login. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

That option concerns BGP route preference sequence and policy precedence. That follows from the targeted Recommended action: Troubleshoot a site-to-site IPsec tunnel by separating IKE security-association establishment from protected ESP payload transport.

That option concerns VRF traffic separation and route leaking controls. That follows from the targeted Recommended action: Troubleshoot a site-to-site IPsec tunnel by separating IKE security-association establishment from protected ESP payload transport.

That option concerns Huawei firewall NAT and address translation context. That follows from the targeted Recommended action: Troubleshoot a site-to-site IPsec tunnel by separating IKE security-association establishment from protected ESP payload transport.

This option proposes: Enable unencrypted Telnet from any source and reuse one shared administrator account because the switch has a separate data-plane ACL. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

This option proposes: Create an inter-zone allow policy and assume that private source addresses will automatically be translated to a publicly routable address with no NAT rule. It addresses the different topic Huawei firewall NAT and address translation context, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

This option proposes: Assume the lowest numerical route preference must always override a longer matching prefix for the same destination regardless of mask length. It addresses the different topic Longest prefix match and route preferences, not the directly tested IPsec VPN IKE negotiation versus ESP data channel failure in the stated incident (An IPsec tunnel shows an established IKE SA but no ESP packet increments because the local and remote protected subnet selectors differ.).

This option proposes: Enforce role-based management authentication and encrypted remote administration instead of relying on shared cleartext or unrestricted control-plane access. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Configure VRRP priority tracking with suitable preemption behavior so loss of upstream connectivity changes the preferred gateway. It addresses the different topic VRRP interface tracking and controlled preemption, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Trace source or destination address translation separately from security policy when applications fail across a routed perimeter. It addresses the different topic Huawei firewall NAT and address translation context, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: AAA separates authentication, authorization and accounting for device management, while SSH protects management sessions and access policies can limit trusted administrative sources. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: IKE negotiates security associations and authenticates peers, while IPsec ESP carries encrypted or integrity-protected traffic as configured; matching peer identities, proposals and traffic selectors are needed for an effective tunnel. It addresses the different topic IPsec VPN IKE negotiation versus ESP data channel, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: MED is an optional nontransitive BGP attribute, with lower values typically favored when compared under applicable rules; it is often compared for routes from the same neighboring AS unless policy changes this behavior. It addresses the different topic BGP MED interpretation between neighboring autonomous systems, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Review the client's roam event timestamps, candidate AP signal conditions, reassociation/authentication records and address or session continuity. It addresses the different topic Wireless roaming mobility and session continuity, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Inspect source and destination zones, policy match, existing session, NAT translation and deny logs for the tested client flow. It addresses the different topic Stateful firewall sessions versus basic packet ACL filtering, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Review phase 1/IKE negotiation logs, IPsec child SA proposals, traffic selectors, encap/decap packet counters and the route to the remote subnet. It addresses the different topic IPsec VPN IKE negotiation versus ESP data channel, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Looping advertisements are rejected and intended route preference changes are explained without promising a universal AS_PATH outcome. It addresses the different topic BGP AS_PATH path-vector loop prevention, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.). The better discriminating check for this case is: Inspect ingress interface VPN instance, per-instance routes, next-hop resolution and authorized route import or interconnect rules. The targeted correction is: Examine per-VRF routing and interface membership before declaring two isolated customer networks mutually reachable.

That option concerns Stateful firewall sessions versus basic packet ACL filtering. That follows from the targeted action: Examine per-VRF routing and interface membership before declaring two isolated customer networks mutually reachable.

That option concerns IPsec VPN IKE negotiation versus ESP data channel. That follows from the targeted action: Examine per-VRF routing and interface membership before declaring two isolated customer networks mutually reachable.

This option proposes: Inspect source and destination zones, policy match, existing session, NAT translation and deny logs for the tested client flow. It addresses the different topic Stateful firewall sessions versus basic packet ACL filtering, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.). The better discriminating check for this case is: Inspect ingress interface VPN instance, per-instance routes, next-hop resolution and authorized route import or interconnect rules.

This option proposes: Troubleshoot BGP establishment by distinguishing TCP port 179 transport, peer configuration and OPEN capability negotiation. It addresses the different topic BGP transport reachability and session states, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.).

This option proposes: Investigate a BGP route that appears in a peer table but fails to install because its NEXT_HOP is unresolved. It addresses the different topic BGP NEXT_HOP reachability and next-hop-self, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A managed service provider supports two tenants using overlapping 10.0.0.0/8 addresses and one tenant unexpectedly sees another's service after an interface is assigned to the wrong VRF.). The better discriminating check for this case is: Inspect ingress interface VPN instance, per-instance routes, next-hop resolution and authorized route import or interconnect rules. The targeted correction is: Examine per-VRF routing and interface membership before declaring two isolated customer networks mutually reachable.

This option proposes: Diagnose firewall traffic by checking stateful session records and security-zone policy rather than treating every permitted ACL packet as an established connection. It addresses the different topic Stateful firewall sessions versus basic packet ACL filtering, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: Enforce role-based management authentication and encrypted remote administration instead of relying on shared cleartext or unrestricted control-plane access. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: Distinguish level-1 area routing from level-2 backbone-style interarea routing when troubleshooting a missing destination. It addresses the different topic IS-IS level one versus level two reachability, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: IKE negotiates security associations and authenticates peers, while IPsec ESP carries encrypted or integrity-protected traffic as configured; matching peer identities, proposals and traffic selectors are needed for an effective tunnel. It addresses the different topic IPsec VPN IKE negotiation versus ESP data channel, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: A stateful firewall tracks valid connection context and can permit related return traffic based on session state; network ACLs may filter packets independently without the same stateful application tracking. It addresses the different topic Stateful firewall sessions versus basic packet ACL filtering, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: OSPF's intra-area SPF calculation prefers the lowest valid accumulated link cost, subject to equal-cost rules; a protocol neighbor being Full alone does not establish path preference. It addresses the different topic OSPF SPF calculation and interface cost changes, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: Review phase 1/IKE negotiation logs, IPsec child SA proposals, traffic selectors, encap/decap packet counters and the route to the remote subnet. It addresses the different topic IPsec VPN IKE negotiation versus ESP data channel, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: Inspect the originating ASBR, type 5 LSA, external metric type and metric, cost toward the ASBR and actual selected external next hop. It addresses the different topic OSPF external LSAs and E1 versus E2 cost, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).

This option proposes: Inspect the user or TACACS/RADIUS identity, assigned privilege, SSH negotiation, source address controls and accounting records for a test login. It addresses the different topic Network device AAA role SSH and management-plane protection, not the directly tested VRF traffic separation and route leaking controls failure in the stated incident (A campus team wants a printer in one VPN instance reachable from a services VPN instance, but both instance routing tables have no authorized connection.).