Topic

Using Virtual Local Area Networks

Applicable to

all

History

Priority

must not

Dec 2021

Network devices managing VLANs belonging to different security domains do not share VLAN trunks.

Miscellaneous changes were made to rationale and security controls throughout the publication. This included:

• A review from the Using the Information Security Manual chapter through to the Guidelines for Media chapter.

• Security controls suitable for all audiences have been identified with the ‘All’ applicability marking while additional security controls suitable for just government audiences have been identified with the O, P, S and TS applicability markings.

• Security controls suitable for specific classifications have been amended to include their classification(s) in the wording of the security controls to reduce the reliance on applicability markings to confer suitability.

• Tables in security controls have been converted into prose to allow for inclusion in the SSP annex template and the XML list of security controls.

• The use of ‘official’ and ‘highly classified’ terminology has been replaced with specific classifications to remove ambiguity.

• Security controls relating to high assurance ICT equipment have had their applicability narrowed to ‘S, TS’ reflecting that they are intended for the protection of SECRET and TOP SECRET systems and data.

2015

VLANs with different classifications must not share VLAN trunks.

2010

VLAN trunking must not be used on switches managing VLANs of differing security domains.

2008

VLAN trunking must not be used on switches managing VLANs of differing classifications.