Cisco Bug: CSCup89922 - ASA DNS lookups always prefer IPv6 response
Aug 14, 2018
- Cisco ASA 5500-X Series Firewalls
Known Affected Releases
9.1(0.2) 9.1(1) 9.1(5)
Symptom: A DNS server configured on the ASA will always use IPv6 DNS requests (type=AAAA) if any of the interfaces are configured with IPv6. There is no way to prevent this behaviour, or make the ASA prefer and sending type=A requests. Conditions: This only occurs if IPv6 is enabled on any interface of the ASA, even if no Globally Unique Address is assigned. If IPv6 is enabled, then the ASA only makes Type=AAAA DNS requests. This will always result in an IPv6 DNS response, and potentially cause features that depend on DNS to fail (ie. Smart Call Home).
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Bug Details Include
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