Lotus domino location settings have to be set to IP address why doesn't it find chicago/admin ?

Today just out of the blue users got the error 'the remote server is not a known tcpip host' all client lotus notes locations are set to chicago/admin but they can't find that now so we replaced the server details with the ip  172.20.1 30.  We have a backup disaster server chicago-dr\admin and they can switch over to that location easily.

How to we get the original location to work again without going to each pc and the server to an ip in the location settings?  Has something happened in DNS settings everything looks ok there is a record for Chicago-Mail1 pointing to which is the mail server.

Any help much appreciated
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1. 172 is a private IP range, so your internal DNS servers should provide clients with the address.  Client machines using only public DNS servers will not be able to resolve the address.

2. there is a mismatch between the names 'chicago/admin' and 'Chicago-Mail1'.  Clients will ask DNS for the address 'chicago', not 'Chicago-Mail1'.

To test, open a command prompt on a client machine.
ping chicago
the client should resolve the address, show it, and execute 4 pings to the resolved address and show the results.  Example:
Pinging chicago [] with 32 bytes of data:
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64

Ping statistics for
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

3. You write about entering the address in the location.  But where do you do that? Because a Connection document should be used to specify the IP address of a server. The server fields in a Location document (e.g. Home/mail server, Passthru server, Catalog/domain search server, Domino directory server) should be specified with the abbreviated Notes name of the server.
On the advanced tab, the possibility exists to specify a secondary server to be contacted for Address Book information in case the home server is not available on the TCP/IP network. The past 15 years I have not seen examples of this being in use for the right reasons, so I recommend resolving DNS connectivity.

Please report back with results from the ping and share any comments/questions you may have.

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