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Cisco Bug: CSCvi66266 - DNS request matching split-DNS domain leaked by Hyper-V host when DNS query issued by Hyper-V guest

Last Modified

Jun 14, 2018

Products (1)

  • Cisco AnyConnect Secure Mobility Client

Known Affected Releases

4.5(2036)

Description (partial)

Symptom:
DNS request targeting third-level domain (e.g. host.company.com) matching split-DNS domain (e.g. second-level  domain company.com) configured on the VPN server is answered via the physical adapter with a response containing an SOA record, clearly indicating that the DNS request was allowed outside the VPN tunnel despite matching a split-DNS domain.

Conditions:
- Platform: Windows 10.
- Split-DNS enabled on the VPN server.
- AnyConnect client host with Hyper-V enabled, DNS request matching split-DNS domain issued from Hyper-V guest also running Windows 10.
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
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