02-22-2019 01:10 PM
I am trying to use hostnames for NTP on a few devices that have a management in a vrf.
I have configured:
ip domain list vrf Mgmt-intf example.com ip domain lookup vrf Mgmt-intf source-interface GigabitEthernet0 ip domain name example.com ip name-server vrf Mgmt-intf 8.8.8.8
When I try to ping an address by name it takes forever for it to actually respond, by forever I am talking minutes!
host#ping vrf Mgmt-intf google.com
It eventually responds but why is it taking so long.
Solved! Go to Solution.
02-22-2019 02:05 PM
Hello,
remove this line:
ip domain lookup vrf Mgmt-intf source-interface GigabitEthernet0
You might be hitting the bug below:
DNS does not resolve hostname when source interface is configured
CSCvk76541
Description
Symptom:
Basic DNS functionality does not work when source interface is configured, as hostname fails to resolve most of the time and takes up to 5 minutes to process. With source interface removed, the hostname resolution is successful every time and processed immediately. Below are the DNS related configs:
ip name-server vrf Mgmt-intf X.X.X.X
ip domain lookup (vrf Mgmt-intf) source-interface GigabitEthernet0
ip domain name vrf Mgmt-intf domain.name.com
Conditions:
The issue is seen when a source interface is configured for DNS, with or without VRF, with management and non-management interfaces. The issue has been observed on ASR1006 running 16.8.1 and ASR1000HX running 16.5.3.
Workaround:
Remove "ip domain lookup (vrf Mgmt-intf) source-interface GigabitEthernet0" command.
02-22-2019 01:48 PM
Hello,
not sure if that command is available on the ASR, but what if you change:
ip domain name example.com
to
ip domain name example.com use-vrf Mgmt-intf
02-22-2019 01:52 PM
Command is there in this format:
ip domain name vrf Mgmt-intf example.com
Doesn't seem to make a difference.
02-22-2019 02:05 PM
Hello,
remove this line:
ip domain lookup vrf Mgmt-intf source-interface GigabitEthernet0
You might be hitting the bug below:
DNS does not resolve hostname when source interface is configured
CSCvk76541
Description
Symptom:
Basic DNS functionality does not work when source interface is configured, as hostname fails to resolve most of the time and takes up to 5 minutes to process. With source interface removed, the hostname resolution is successful every time and processed immediately. Below are the DNS related configs:
ip name-server vrf Mgmt-intf X.X.X.X
ip domain lookup (vrf Mgmt-intf) source-interface GigabitEthernet0
ip domain name vrf Mgmt-intf domain.name.com
Conditions:
The issue is seen when a source interface is configured for DNS, with or without VRF, with management and non-management interfaces. The issue has been observed on ASR1006 running 16.8.1 and ASR1000HX running 16.5.3.
Workaround:
Remove "ip domain lookup (vrf Mgmt-intf) source-interface GigabitEthernet0" command.
02-22-2019 02:08 PM
02-22-2019 02:12 PM
Hello,
unfortunately the bug doesn't mention a release with a fix, so for now, you are 'stuck' with the workaround...
02-22-2019 02:13 PM
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