Long DNS timeout and ip domain timeout is removed :(

[steffenschumacher]

Hi,

in 16.9.4 ip domain timeout is removed, as its now based on the RTD of nameservers - and that's probably good if it worked, but check out this:

dklab4-dr01#show clock
08:40:00.570 CET Tue Dec 22 2020
dklab4-dr01#ping klaf 
% Unrecognized host or address, or protocol not running.

dklab4-dr01#show clock
08:42:41.927 CET Tue Dec 22 2020

So roughly 150 seconds before timeout - that really sucks. Nameservers are reached via DMVPN, but I can't see how that should be the issue?

When I lookup existing hosts, it all works fine and quickly - anyone else seeing this?

Im using C1111-8P for this

[balaji.bandi]

Not sure i am able to understand the issue :

do you have DNS configured, and is that reachable? then it should resolve, this is more of  host entry by localhost not by FQDN

Generally, depends on TTL and every 3 seconds it retries - but depends on IOS what default set here. 

you need to have Local DNS also configured in case not able to reach the global one it can reach local DNS for your host entries.

https://www.cisco.com/c/en/us/support/docs/ip/domain-name-system-dns/24182-reversedns.html

[steffenschumacher]

Yes, DNS is configured, and working fine for stuff which actually exists - like google.com or similar. so if I do 'ping somethingnonexisting' then it will try to resolve 'somethingsnonexisting' and this part will take up to 150 seconds to fail, which I'd like to cut down to ~2-3 seconds if possible.

If I do 'ping google.com' it resolves it nice and fast.

This is mostly to avoid a hanging console when a typo is made, as waiting 150 seconds every time a typo happens is not super effective..

[balaji.bandi]

Is this DNS Configured Local DNS or Public DNS

if you have issue with local DNS taking long time, i would suggest to use Local DNS as Primary to minimise the issue,

[steffenschumacher]

Its an internal DNS server(s) but its close by:

Success rate is 100 percent (5/5), round-trip min/avg/max = 20/23/24 ms

and responds super fast, whenever the query is successful - its only when I'm querying bogus stuff it takes forever (150 secs)

[balaji.bandi]

Device can not hold that information - so it wait for DNS to respond back or TTL expirty.

[egoepfert]

I'm having the same problem.  We like to have resolution turned on for the items with actual entries, but not every IP has a DNS name, so when you do a command like 'show ip ospf neighbor' anything with a name comes back super fast, but then it waits 150+ seconds to timeout per line on the command.

There NEEDS to be a wait to set DNS timeout/retries because this is silly.

[balaji.bandi]

what is the device and IOS Code running :

Can check the DNS view

#show ip dns view

[steffenschumacher · Accepted solution]

I'm now in 17.3.5 and the issue has gone - not sure if it can reproduced..
dns view says:
XXXXXX#show ip dns view
DNS View default parameters:
DNS Resolver settings:
Domain lookup is enabled
Default domain name: vestas.net
Domain search list: vestas.net
Domain name-servers:
10.x.y.z
10.x.y.j
[two public DNS server IPs..]
DNS Server settings:
Forwarding of queries is enabled
Forwarder addresses: