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FQDN converted to IP address

Frequent Contributor
Frequent Contributor

I am trying to setup time service on two devices.  Once is a UC520, the second an 1840 router.  I would like to use the FQDN of the time server which is  This is the recommended procedure as per due to changes of IP addresses of time servers.

On the UC520 this is not a problem.  I type in "ntp server" and this is how the command stays in the config.  On the 1800 the FQDN is resolved and inserted into the config as an IP address.  This works for now but kinda defeats the purpose of using a FQDN.

How can I keep the 1800 from converting to IP?




paolo bevilacqua
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Please be aware that even if the domain name stays in config, that does NOT mean the router will follow any change in the corresponding A record after it is configured. It will NOT.

So, the whatever IOS is running on the 1800 is doing the right thing, it resolves the domain to IP once and leave the latter in config instead of fooling you in thinking that the router will follow DNS in NTP - again, it will not.

In any case, the difference is due to different IOS version

That's the way NTP works on IOS - it uses addresses only. Be that right or wrong, we can't change it

If you don't like it please don't complain to me - complain to Cisco.

Not complaining to anyone. Just wanted to know what is going on.

Thanks for the info.



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