This requirement is not applicable for the DODIN Backbone. Review the router configuration to verify uRPF or an egress filter has been configured on all internal interfaces to restrict the router from accepting outbound IP packets that contain an illegitimate address in the source address field. [edit interfaces] <internal interface name> { unit <number> { family inet { rpf-check; address <IPv4 address>/<mask>; } family inet6 { rpf-check; address <IPv6 address>/<prefix>; } } } For those platforms that do not support uRPF, verify an egress stateless firewall filter is applied to all internal interfaces. In this example, the egress (from the enclave) filter is applied in the input direction of internal interfaces to prevent the router from accepting packets sourced from any address except the internal subnets. For example: [edit policy-options] prefix-list internal-prefixes-ipv4 { 192.0.2.0/24; } prefix-list internal-prefixes-ipv6 { 2001:0:2::/64; } [edit firewall] family inet { filter internal-inbound-ipv4 { term 1 { from { source-prefix-list { internal-prefixes-ipv4; } } then accept; } term default { then { log; syslog; discard; } } } } family inet6 { filter internal-inbound-ipv6 { term 1 { from { source-prefix-list { internal-prefixes-ipv6; } } then accept; } term default { then { log; syslog; discard; } } } } Verify the appropriate filter is applied to each internal interface. For example: [edit interfaces] <internal interface name> { unit <number> { family inet { filter { input internal-inbound-ipv4; } address <IPv4 address>/<mask>; } family inet6 { filter { input internal-inbound-ipv6; } address <IPv6 address>/<prefix>; } } } Note: Some Juniper devices support both monolithic filters and filter lists. Filter lists separate each term, or set of terms, into a separate filter that is applied sequentially to an interface. If using filter lists, the keywords "input" or "output" change to "input-list" or "output-list". Verify the final list item is a deny-all filter. The deny-all filter is created once per family and can be reused across multiple lists. For example: input-list [ permit_mgt permit_routing_protocols default-deny ]; If uRPF or an egress filter to restrict the router from accepting outbound IP packets that contain an illegitimate address in the source address field has not been configured on all internal interfaces, this is a finding.