"Device not configured" from Dns.GetHostEntryAsync on macOS #19222
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Have just reproduced this and its causing us a nightmare. Works fine in netcoreapp1.0 but netcoreapp1.1 explodes with above exception. We have production systems wanting to move to 1.1 ASAP but can't |
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cc: @geoffkizer, is this something you could investigate? |
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@Priya91 can you please help here? |
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@jchannon What is the host value for which you get this error? .Net error string Device not configured is thrown for host not found error. This function ultimately calls gethostbyname() native OS API, it will be valuable to get this datapoint. Looking into how this error string gets it's value from. |
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An ip address
…On Thu, 19 Jan 2017 at 02:50, Lakshmi Priya Sekar ***@***.***> wrote:
@jchannon <https://github.com/jchannon> What is the host value for which
you get this error?
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here is my investigation from other issue on Mac SO @stephentoub @Priya91 I heard from @karelz that you are contacts for the non Windows networking issues. on Sierra, there are a couple of net tests are failing for the same reason. what is happening is we are calling gethostname() which will return the current local host name (something like Tarek-MacBook-Pro.local and then we try to get the host entry info by calling gethostbyname() and passing the local host name we got from gethostname(). gethostbyname() is failing with the error HOST_NOT_FOUND. I have tried to run getent hosts and it shows the only registered host is localhost. in other Linux machines the command show the expected full local host name. also on Mac OS there is other failure caused by same reason: <test name="System.Net.NameResolution.PalTests.NameResolutionPalTests.GetHostByName_HostName" type="System.Net.NameResolution.PalTests.NameResolutionPalTests" method="GetHostByName_HostName" time="5.025076" result="Fail">
<failure exception-type="System.Net.Internals.SocketExceptionFactory+ExtendedSocketException">
<message><![CDATA[System.Net.Internals.SocketExceptionFactory+ExtendedSocketException : Device not configured]]></message>
<stack-trace><![CDATA[ at System.Net.NameResolutionPal.GetHostByName(String hostName) in /private/tmp/corefx/src/System.Net.NameResolution/src/System/Net/NameResolutionPal.Unix.cs:line 151
at System.Net.NameResolution.PalTests.NameResolutionPalTests.GetHostByName_HostName() in /private/tmp/corefx/src/System.Net.NameResolution/tests/PalTests/NameResolutionPalTests.cs:line 40]]></stack-trace>
</failure>
</test> |
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@jchannon Can you provide a repro of the failure, the test bug is probably because GetHostEntryAsync failed on mac OS due to incorrect machine dns configuration. Trying host would have produced error host not found. We haven't had this test fail since on any of our CI machines, so I need more info to resolve your issue. I used the following code with .NET Core 1.1 on OS X 10.10.5, using System;
using System.Net;
namespace ConsoleApplication
{
public class Program
{
public static void Main(string[] args)
{
Console.WriteLine(Dns.GetHostName());
Console.WriteLine(Dns.GetHostEntryAsync(Dns.GetHostName()).GetAwaiter().GetResult().AddressList[0]);
}
}
}and got this output, Please provide more info for further investigation. |
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I ran that same code with .NET Core 1.1 on macOS 10.12.3 (16D32) and got an exception. I wonder if something changed in the networking stack of newer versions of macOS. |
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@yaakov-h I dont think it's the stack that's changed, as i just updated my mac today, and ran the program, it worked as expected. What the api does is call into gethostbyname or getaddrinfo to perform dns lookup. The error is what the exception states, that the dns servers may not be configured for your mac. You can follow the documentation here to verify that. Closing the issue due to lack of information to proceed further. Please reopen with new info. |
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@Priya91 there are definitely DNS servers configured... and I can resolve other addresses as is evidenced by being able to resolve GitHub.com to post in this issue. Similarly, if it was just a case of the Mac's own name not being known in reverse lookup, I'd expect What further info can I get, aside from dropping a laptop in the post (not gonna happen)? |
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@yaakov-h given that we cannot reproduce the issue locally, the best thing is for you to debug the issue on your machine down to Mac APIs calls. Will they fail if you call them with the same values from native app? |
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@yaakov-h here's a sample native code with gethostbyname you can use to run on your laptop and what's the output? #include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <arpa/inet.h>
int main(int argc, char **argv)
{
if (argc < 2)
{
printf("Usage: %s hostname\n", argv[0]);
exit(-1);
}
printf("GetHostByName results:\n");
// gethostbyname
struct hostent *hp = gethostbyname(argv[1]);
if (hp == NULL)
{
printf("gethostbyname() failed\n");
printf("%s: %d\n", hstrerror(h_errno), h_errno);
char buffer[500];
strerror_r(h_errno, buffer, 500);
printf("strerror_r: %s", buffer);
printf("\n");
}
else
{
printf("%s = ", hp->h_name);
unsigned int i=0;
while (hp->h_addr_list[i] != NULL)
{
printf("%s ", inet_ntoa(*(struct in_addr*)(hp->h_addr_list[i])));
i++;
}
printf("\n");
}
printf("GetAddrInfo results:\n");
// getaddrinfo
struct addrinfo *result, *rp, hints;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_flags = 0x02;
hints.ai_protocol = 0;
s = getaddrinfo(argv[1], NULL, &hints, &result);
if (s != 0)
{
printf("getaddrinfo() failed\n");
printf("%s %d\n", gai_strerror(s), s);
char buffer[500];
strerror_r(h_errno, buffer, 500);
printf("strerror_r: %s", buffer);
printf("\n");
}
else
{
printf("%s = ", result->ai_canonname);
char str[INET6_ADDRSTRLEN];
for (rp = result; rp != NULL; rp = rp->ai_next)
{
inet_ntop(AF_INET6, rp->ai_addr->sa_data, str, INET6_ADDRSTRLEN);
printf("%s ", str);
}
}
printf("\n");
freeaddrinfo(result);
return 0;
}This is the output: |
I did some experimenting and comparing against another laptop, and I can now reproduce the case 100%. Seemingly, macOS cannot resolve it's own hostname (including |
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I ran into the "Device not configured" error with the above C# code by just being disconnected from Wifi. I was also able to duplicate this by having DNS servers that didn't recognize my machine in the DNS settings for my connection. Note that I'm pretty sure my macbook does have file sharing turned off. It is controlled by our IT department and I have no control over that setting. macOS: 10.12.4 Tested with both 1.0 and 1.1 applications. I ended up fixing this (at least for local machine connections) in our code by just checking if the target host was the "localhost" and switching to the Loopback IP Address. if(Dns.GetHostName() == Destination.Host)
{
return Client.ConnectAsync(IPAddress.Loopback, Destination.Port);
}
return Client.ConnectAsync(Destination.Host, Destination.Port); |
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It's not clear if this is fixed (just says 'closed'), but I believe a workaround to be adding the machine name to the /etc/hosts file (at least on MacOS), with 127.0.0.1 as the address. I'm guessing there is a fix and it will be in the 2.0 release. |
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Is there any progress on this issue? I'm getting it here as well... |
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@galvesribeiro it was closed as "not reproducible" based on the comments above. If you have repro, which repros everywhere or if you have a fix, please let us know. |
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@karelz I noticed that it happens on my office network but not on my home one. It looks like the OSX DNS can't resolve by itself its own hostname so it rely on the DNS configured to it.
If the hostname DNS can't be resolved by the DNS server (the wifi router in this case) then we have a failure. My router at home (Amplifi) register every device it assign an IP on DHCP on its own DNS. So when OSX makes a DNS request to resolve it, it get the proper IP and don't fail. I just think the exception from corefx should not be "Device not ready" but a "Can't resolve hostname" or something. |
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"Device not configured" is what strerror gives for ENXIO, which is what we are supplying it for the HostNotFound case: { SocketError.HostNotFound, Interop.Error.ENXIO }, // not perfect, but closest match availableI see in some configurations ENXIO produces "No such device or address" which probably why it was used for HostNotFound. Perhaps that changed in recent versions of macOS? It could use EHOSTUNREACH (something like "No route to host") but of course that's not the same - the host isn't resolved at all. I'm not sure where to look for the updated list of error strings on macOS - I looked at https://opensource.apple.com/source/gcc/gcc-5664/libiberty/strerror.c.auto.html and it says "No such device or address". @galvesribeiro what macOS version is this? Another option is to use our own string in this particular case. It won't be localized, though. |
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I'll reactivate this for that suggestion. |
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@stephentoub on High Sierra ENXIO gives "Device not configured" apparently instead of "No such device or address". Would it be reasonable for us to use our own string for this error code, possibly on macOS only? |
Is there a better errno value we could map to instead? EADDRNOTAVAIL? EHOSTUNREACH? |
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As above, EHOSTUNREACH is misleading as it means that we have an IP address, which we don't. |
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@danmosemsft Sorry, I just got out on vacation with limited access to computer. If none else try that, I can try Dec 3th when I got back. |
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I had same issue on my Mac, just fixed like what @CleverCoder said as above, MacOS: |
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Just edit localhost using 127.0.0.1 |
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I wrote simple C program: #include <stdio.h>
#include <errno.h>
#include <string.h>
int main(int argc, char ** argv){
printf("ENXIO: %s\n",strerror(ENXIO));
printf("EADDRNOTAVAIL: %s\n",strerror(EADDRNOTAVAIL));
printf("ENONET: %s\n", "?????");
printf("EHOSTDOWN: %s\n",strerror(EHOSTDOWN));
printf("EDESTADDRREQ: %s\n",strerror(EDESTADDRREQ));
printf("ENOENT: %s\n",strerror(ENOENT));
return 0;
}on Linux: OSX: FreeBSD strangely, "no such file" seems most intuitive. For comparison, Curl HTTP Handler throws " Couldn't resolve host name". I think the flaw is attempt to map NDS error to errno and than use strerror() instead of gai_strerror() |
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I have 2 WiFI Networks at home and I have the same issue on .NET Core 2.0. The following Error appears: As I can easily reproduce the error switching from one network to the other, I could help someone more experienced track down the difference and what's causing this. |
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The error is misleading. This is caused by DNS lookup failures. It seems like one of you networks does have some issues. You can try to resolve the name with nslookup, just to see if it is working properly. |
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Just out of the blue I got this exception using Npgsql. For me it didn't get fixed by adding my the hostname to /etc/hosts However the most interesting part: is that the exception only raises when starting the application from command line ( -- EDIT / Solution: Apparently I forgot to set the environment variable, which configures which connection string I use.. Being that the connection string defaults that should be ran in docker-compose, it is a hostname that is unable to resolve outside that network. So maybe the error message is just misleading, and should it report something along the lines of "Failed to lookup 'xxx'". Please do, include the value of the parameter that has been given, that would have saved me quite some time. |
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Just thought I'd contribute what I've found out while running into this same issue. I was having trouble with the I got around this by creating a Uri with uri builder, then passing in the host to ping. Here's my workaround: Uri uri;
if (Uri.TryCreate(distributor.server, UriKind.Absolute, out uri))
{
Ping _ping = new Ping();
PingReply _reply = await _ping.SendPingAsync(uri.Host, 4000);
if (_reply.Status == IPStatus.Success)
return Ok(true);
}
return Ok(false); |
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I have solve this problem using 127.0.0.1 address instead "localhost" as server name. |
Thank you!!! I was connecting to a server using a corporate proxy and kept getting By removing the protocol from the proxy I was able to connect just fine. |
ghost
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https://ci.dot.net/job/dotnet_corefx/job/master/job/osx_debug_prtest/2571/consoleText
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