Bug 35536

Summary: Dns.GetHostEntry no longer supports IPv6
Product: [Mono] Class Libraries Reporter: matt
Component: SystemAssignee: Marek Safar <masafa>
Status: CLOSED FIXED    
Severity: normal CC: alexandre.marcondes, masafa, mono-bugs+mono, saurabhd
Priority: ---    
Version: 4.0.0   
Target Milestone: 4.8.0 (C9)   
Hardware: Macintosh   
OS: Mac OS   
Tags: Is this bug a regression?: ---
Last known good build:

Description matt 2015-11-04 11:49:16 UTC
Dns.GetHostEntry used to return IPv4 and/or IPv6 addresses when appropriate. It now no longer works with IPv6.

This throws an exception
var hostEntry = Dns.GetHostEntry("ipv6.google.com").AddressList;

This returns a list of only IPv4 addresses
var hostEntry = Dns.GetHostEntry("google.com").AddressList;
Comment 1 Marek Safar 2016-11-15 12:29:35 UTC
Fixed in master and Mono 4.8
Comment 2 Saurabh 2016-11-21 11:26:53 UTC
I have checked this Issue with latest master build (Mono 4.9.0.970). I am still getting exception when using ipv6. 

Exception details: https://gist.github.com/saurabh360/0ae7d62eeff087adfcaa8de01e6efcbe

Environment Info: https://gist.github.com/c16d963aa7ea93d0ba15194248e76941
Comment 3 Marek Safar 2016-11-23 17:12:21 UTC
@Saurabh Do you really have IPv6 network working e.g does ping to ipv6 address work for you?
Comment 4 Saurabh 2017-02-07 07:40:25 UTC
I have checked it again and I am using IPv6 network and still getting exception.
Screencast: https://www.screencast.com/t/l6xhNKoRMc
Exception details: https://gist.github.com/AkhileshKumar01/ab907439486a2911c060ac4ae6c73f6f
Environment Info: https://gist.github.com/AkhileshKumar01/3f2844619e5665528b7f80d4855408e2
Comment 5 Marek Safar 2017-02-07 08:39:30 UTC
Does ping to ipv6 from terminal work ?
Comment 7 Marek Safar 2017-02-08 12:37:04 UTC
If you cannot ping ipv6 google server from terminal it'll hardly work from the app. You should see something like if your network is ipv6/dns6.

ping6 ipv6.google.com
PING6(56=40+8+8 bytes) 2a01:110:1008:40:5cb3:3661:6720:35ee --> 2a00:1450:4009:800::200e
16 bytes from 2a00:1450:4009:800::200e, icmp_seq=0 hlim=47 time=28.946 ms
16 bytes from 2a00:1450:4009:800::200e, icmp_seq=1 hlim=47 time=28.878 ms
16 bytes from 2a00:1450:4009:800::200e, icmp_seq=2 hlim=47 time=27.303 ms
16 bytes from 2a00:1450:4009:800::200e, icmp_seq=3 hlim=47 time=27.433 ms


You could also check http://ipv6-test.com/
Comment 8 Saurabh 2017-02-21 07:36:43 UTC
@Marek, I have again tried to setup ipv6 locally using mac with document: https://developer.apple.com/library/content/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/UnderstandingandPreparingfortheIPv6Transition/UnderstandingandPreparingfortheIPv6Transition.html and checked that ipv6 address appearing in network preference but when I am checking using http://ipv6-test.com/ It is showing me not supported for both ipv4 and ipv6. This is the screencast for the same: https://www.screencast.com/t/g7IltjZF

Could you please let me know how can I setup this ipv6 so that I can verify this Issue?
Comment 9 Marek Safar 2017-02-21 08:58:07 UTC
I have no idea how your local network is setup, it's best to talk to your network administrator how to make ipv6 work for you