ARST-L2-000160 - The Arista MLS layer 2 switch must have all trunk links enabled statically.

Information

When trunk negotiation is enabled via Dynamic Trunk Protocol (DTP), considerable time can be spent negotiating trunk settings (802.1q or ISL) when a node or interface is restored. While this negotiation is happening, traffic is dropped because the link is up from a layer 2 perspective. Packet loss can be eliminated by setting the interface statically to trunk mode, thereby avoiding dynamic trunk protocol negotiation and significantly reducing any outage when restoring a failed link or switch.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure static Ethernet interfaces for switchport trunk mode. Ensure required VLAN member tagged traffic is allowed and all other VLAN traffic will be dropped unless an associated untagged native VLAN for the Ethernet interface is allowed.

switch#configure
switch(config)#interface Ethernet6
description STIG Static Trunk
speed forced 10000full
switchport trunk native vlan 2102
switchport trunk allowed vlan 2100-2102
switchport mode trunk
!
switch(config)#interface Ethernet7
description STIG Static Trunk
speed forced 10000full
switchport trunk native vlan 3102
switchport trunk allowed vlan 3100-3102
switchport mode trunk
!

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Arista_MLS_EOS_4-2x_Y23M02_STIG.zip

Item Details

References: CAT|II, CCI|CCI-000366, Rule-ID|SV-255979r882279_rule, STIG-ID|ARST-L2-000160, Vuln-ID|V-255979

Plugin: Arista

Control ID: d45b8491cad2d993514fd2521b0c8d5609f3c6c988bdf7534ef06e3f6d50bb34