ASG
IBM
Zystems
Cressida
Icon
Netflexity
 
  MQSeries.net
Search  Search       Tech Exchange      Education      Certifications      Library      Info Center      SupportPacs      LinkedIn  Search  Search                                                                   FAQ  FAQ   Usergroups  Usergroups
 
Register  ::  Log in Log in to check your private messages
 
RSS Feed - WebSphere MQ Support RSS Feed - Message Broker Support

MQSeries.net Forum IndexGeneral IBM MQ SupportIssues with reverse DNS lookup in Windows 10

Post new topicReply to topic
Issues with reverse DNS lookup in Windows 10 View previous topic :: View next topic
Author Message
jamesb
PostPosted: Fri Oct 25, 2019 6:51 am Post subject: Issues with reverse DNS lookup in Windows 10 Reply with quote

Newbie

Joined: 09 Mar 2008
Posts: 2

Hi all, Does anyone here still use rfhutilc and, in particular, on Windows 10 desktop? The scenario is this: We are running an MQ v8 server on Linux and our support team have been using rfhutilc on Windows 7 to put/get/move messages, etc. That was working fine using the DNS name of our MQ server to connect in the connection string of the form
CHANNEL_NAME/TCP/HOST_NAME.com(Port)
in the first box, Queue manager connection.
They've now 'upgraded' to Windows 10 and it no longer works with the DNS name in the connection string and we have to use the IP instead. With DNS it fails with 'host not available', 2538. Doing a bit of reading around it sounds like the DNS lookup/reverse DNS lookup may not be working correctly in windows 10 and when I did a client trace it looked like it was confirming a failure in the DNS lookup.
RSESS:000001 xcsIsEnvironment[AMQ_NO_IPV6] = FALSE
RSESS:000001 ----------} xcsIsEnvironment (rc=OK)
RSESS:000001 ----------{ cciTcpResolveHostname
RSESS:000001 Hostname: 'mycorrecthostname.com'
RSESS:000001 getaddrinfo(): AF_INET & AI_NUMERICHOST: rc=11001 errno=2
RSESS:000001 getaddrinfo(): AF_INET6: rc=11001 errno=2
RSESS:000001 getaddrinfo(): AF_INET: rc=11001 errno=2
RSESS:000001 serv_addr4
RSESS:000001 Data:-
RSESS:000001 0x00EFC400 00 00 20 77 00 00 00 00 00 00 00 00 00 00 00 00 : .. w............
RSESS:000001 serv_addr6
RSESS:000001 Data:-
RSESS:000001 0x00EFC42C 00 00 20 77 00 00 00 00 00 00 00 00 00 00 00 00 : .. w............
RSESS:000001 0x00EFC43C 00 00 00 00 00 00 00 00 00 00 00 00 : ............
RSESS:000001 ----------}! cciTcpResolveHostname (rc=rrcE_HOST_NOT_AVAILABLE)
There's definitely no issue with the correct hostname I am using so no typo error. This was with an old version of rfhutilc as well as the latest version I downloaded from git. The trace runs fine on windows 7 and the DNS is resolved correctly. However, we have no issue using the MQ v8 Explorer from Windows 10 with the DNS name to connect to our queue managers and it resolves it with no issues. Can anyone point me in the right direction here to understand what the issue is running from rfhutilc on win10 and if it's 'fixable'?
Thanks, James.
Back to top
View user's profile Send private message
HubertKleinmanns
PostPosted: Fri Oct 25, 2019 7:15 am Post subject: Reply with quote

Shaman

Joined: 24 Feb 2004
Posts: 724
Location: Germany

I don't think, that "rfhutilc" or the MQ Explorer have implemented a DNS resolution functionality. This is should have been done by Windows. May be, that there are several system calls, to resolve DNS names, and "rfhutilc" and MQ Explorer use different ones. But nevertheless you should address this to the Windows people.

Possibly as a work-around you could add the names to a "hosts" file, which you should find in:
Code:
C:\Windows\System32\drivers\etc

_________________
Regards
Hubert
Back to top
View user's profile Send private message Visit poster's website
hughson
PostPosted: Fri Oct 25, 2019 2:27 pm Post subject: Reply with quote

Grand Master

Joined: 09 May 2013
Posts: 1283
Location: Bay of Plenty, New Zealand

Neither rfhutil, nor MQ Explorer are responsible for the DNS lookup (FYI, your title is misleading, this is not reverse lookup). The MQ Client is making the call to resolve the hostname into an IP address. The difference between rfhutil and MQ Explorer is likely the difference between the call to resolve a hostname in 'C' versus in Java.

Try, for example, running amqsputc with an MQSERVER environment variable set to use the hostname rather than the IP address - should see same failure.

The error shown in your trace, 11001 is WSAHOST_NOT_FOUND.

What is the result of:-

Code:
nslookup mycorrecthostname.com


Cheers,
Morag
_________________
Morag Hughson @MoragHughson
IBM MQ Technical Education Specialist
Get your IBM MQ training here!
MQGem Software
Back to top
View user's profile Send private message Visit poster's website
fjb_saper
PostPosted: Fri Oct 25, 2019 4:56 pm Post subject: Reply with quote

Grand High Poobah

Joined: 18 Nov 2003
Posts: 20138
Location: LI,NY

As you are dealing with windows and dns lookup, I strongly encourage you to also do a ping -a hostname. We had a problem where IPV6 was not configured, still active and all hostnames came back to ::1 ! Thank you very much!

Disabling IPV6 on the box solved the problem, and the ping came back with the right IPV4 address.

Have fun
_________________
MQ & Broker admin
Back to top
View user's profile Send private message Send e-mail
PeterPotkay
PostPosted: Sat Oct 26, 2019 4:12 am Post subject: Reply with quote

Poobah

Joined: 15 May 2001
Posts: 7582

Also, always fully qualify your names as a best practice.

Instead of calling:
myservername

Call:
myservername@yourdomainname.com (or however your company fully qualifies their DNS names)

For whatever reason that I not felt worth researching any further, my work laptop sometimes (not always) stops resolving some (not all) DNS names that are not fully qualified. I just always fully qualify them and no longer have this issue.
_________________
Peter Potkay
Keep Calm and MQ On
Back to top
View user's profile Send private message
Display posts from previous:
Post new topicReply to topic Page 1 of 1

MQSeries.net Forum IndexGeneral IBM MQ SupportIssues with reverse DNS lookup in Windows 10
Jump to:



You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Protected by Anti-Spam ACP


Theme by Dustin Baccetti
Powered by phpBB 2001, 2002 phpBB Group

Copyright MQSeries.net. All rights reserved.