Should a DNS lookup of a 3cx stun server return one or two IP's

[pecc]

Should a NDS lookup of say stun-eu.3cx.com return one or two IP's?
According to https://www.3cx.com/community/threads/3cx-sip-alg-failed.55338/ each of the stun servers has a +1 IP
When I do a host A lookup of stun-eu.3cx.com it returns 151.80.125.93 but I'm also seeing traffic from 151.80.125.94.

 

[leejor]

Yes they have two IPs, see
https://www.3cx.com/pbx/what-is-a-stun-server/

This has a good diagram of the process...
https://en.wikipedia.org/wiki/STUN

 

[pecc]

Hi Leejor,
Thank you for the feedback (the RFC's make for hardreading) but me question is; should one or both IP's associated with a FQDN be returned when querying DNS?

 

[leejor]

If it do a Tracert on stun-eu.3cx.com , I get one IP, which is to be expected (151.80125.107), but the STUN server is associated with two IPs. as per the 3CX article. I'm not aware of a DNS query returning more than one IP.

 

[pecc]

Leejor, cheers for the feedback, appreciated.

 

[StefanW]

no, the second one you will not see in DNS lookups, PBX sends a request to know IP, from an unknown IP an answer is sent (this IP sits on the same server). If the PBX gets the Answer from this second IP / Port then the PBX knows it has a working full cone nat.