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Micro Focus Expert
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(DP) Support Tip: ipw_getaddrinfo(hostname) Network performance warning

Error Message
Network performance warning appears even though hostname can be resolved by /etc/hosts file without DNS .

- debug.log
12/25/17 10:31:26 VBDA.7922.0 ["/lib/ipc/ipc.c $Rev: 37418 $ $Date:: 2013-05-16 13:47:44":602] A.08.00 b596
ipw_getaddrinfo(hostname) Network performance warning: took 31.000000 sec

- nsswtich.conf
hosts: files [NOTFOUND=continue UNAVAIL=continue] dns
ipnodes: files [NOTFOUND=continue] dns

Cause
Even though IPv4 address can be resolved , IPv6 address is also tried to be resolved .
If /etc/hosts file doesn't contain about the IPv6 address for the hostname , DNS will be referred according to nsswitch.conf file .

Workaround / Fix
It can be considered to remove the 'dns' entry from the ipnodes line in nsswitch.conf file when IPv6 is not used on the system .
If IPv6 is used , the IPv6 address can be written in /etc/hosts file to avoid DNS reference .

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4 Replies
Knowledge Partner Knowledge Partner
Knowledge Partner

Re: (DP) Support Tip: ipw_getaddrinfo(hostname) Network performance warning

I think this kind of warning is highly related to QCCR2A78002.

Reduce delays when performing DNS queries
https://softwaresupport.softwaregrp.com/group/softwaresupport/search-result/-/facetsearch/document/KM03092980

Regards,
Sebastian Koehler

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Micro Focus Expert
Micro Focus Expert

Re: (DP) Support Tip: ipw_getaddrinfo(hostname) Network performance warning

The solution to avoid the message ipw_getaddrinfo(hostname) Network performance warning on unix server is to change the nsswitch.conf so that IPv6 address are only resolved using host files and not using DNS and it works.

My customer is having the same issue on windows 2008 R2 server.

How can I tell windows not to use DNS for IPv6 names resolution ?

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Micro Focus Expert
Micro Focus Expert

Re: (DP) Support Tip: ipw_getaddrinfo(hostname) Network performance warning

Yes, QCCR2A78002 is the result I worked on the issue .

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Micro Focus Expert
Micro Focus Expert

Re: (DP) Support Tip: ipw_getaddrinfo(hostname) Network performance warning

hmm, the topic is specific to windows that I'm not familiar with .
You might need to ask Windows support community , but I'll try to leave some idea .

- If IPv6 is not used at the environment , IPv6 can be disabled at network adapter configuration
- If IPv6 is used , IPv6 address should be described in hosts file
- If IPv4 needs to be used with a priority than IPv6 in the environment , you might need to confirm the priority setting .

C:\>netsh interface ipv6 show prefixpolicies
Querying active state...

Precedence Label Prefix
---------- ----- --------------------------------
50 0 ::1/128
40 1 ::/0
30 2 2002::/16
20 3 ::/96
10 4 ::ffff:0:0/96
5 5 2001::/32


::ffff:0:0/96 is IPv4 map .
If ::ffff:0:0/96 is lower than others , IPv6 will have a priority . (default)
It can be modified by netsh command to let IPv4 have a priority .

ex.)
netsh interface ipv6 set prefixpolicy ::ffff:0:0/96 50 0
netsh interface ipv6 set prefixpolicy ::1/128 40 1
netsh interface ipv6 set prefixpolicy ::/0 30 2
netsh interface ipv6 set prefixpolicy 2002::/16 20 3
netsh interface ipv6 set prefixpolicy ::/96 10 4

 

I hope it helps .

Thank you.
Best regards.
Tadashi

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