300-430 · Question #40
Which two restrictions are in place with regards to configuring mDNS? (Choose two.)
The correct answer is C. mDNS is not supported on FlexConnect APs with a locally switched WLAN. E. mDNS is not supported over IPv6.. mDNS on Cisco WLC has two key restrictions - it is not supported on locally switched FlexConnect WLANs and does not operate over IPv6.
Question
Which two restrictions are in place with regards to configuring mDNS? (Choose two.)
Exhibit
Options
- AmDNS uses only UDP port 5436 as a destination port.
- BmDNS cannot use UDP port 5353 as the destination port.
- CmDNS is not supported on FlexConnect APs with a locally switched WLAN.
- DController software must be newer than 7.0.6+.
- EmDNS is not supported over IPv6.
How the community answered
(50 responses)- A6% (3)
- B4% (2)
- C88% (44)
- D2% (1)
Why each option
mDNS on Cisco WLC has two key restrictions - it is not supported on locally switched FlexConnect WLANs and does not operate over IPv6.
mDNS uses UDP port 5353 as its well-known destination port, not 5436; 5436 has no relevance to mDNS.
UDP port 5353 is the correct and required destination port for mDNS - stating it cannot use this port is the opposite of how the protocol works.
FlexConnect APs in local switching mode bypass the WLC for data traffic, so mDNS packets never reach the controller's mDNS snooping and proxy function, making the feature non-operational in that mode.
No documented Cisco restriction ties mDNS support to a minimum controller software version of 7.0.6+; this version threshold is not a stated restriction.
Cisco's WLC mDNS implementation relies on IPv4 multicast group 224.0.0.251 and does not support the IPv6 equivalent (FF02::FB), so mDNS services cannot be bridged or proxied over IPv6.
Concept tested: mDNS support restrictions on Cisco WLC
Source: https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-0/configuration-guide/b_cg80/b_cg80_chapter_01111001.html
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