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I have a small office network with a handful of Windows / Ubuntu machines of varying releases. A few days ago, one Windows machine lost the ability to access any services on the Ubuntu machines by hostname.

I can resolve the Ubuntu hostname using DNS:

C:\>nslookup gruit
Server:  router.asus.com
Address:  192.168.73.1

Name:    gruit
Address:  192.168.73.152

But, I cannot use things like ping, ftp, ssh, etc. by hostname. For example:

C:\>ping gruit
Ping request could not find host gruit. Please check the name and try again.

I can successfully use the IP address with any of those commands:

C:\>ping 192.168.73.152

Pinging 192.168.73.152 with 32 bytes of data:
Reply from 192.168.73.152: bytes=32 time<1ms TTL=64

I can also use the hostname with a . at the end:

C:\>ping gruit.

Pinging gruit [192.168.73.152] with 32 bytes of data:
Reply from 192.168.73.152: bytes=32 time<1ms TTL=64

This smacks of a NetBIOS issue. Indeed, things like NET VIEW fail:

C:\>net view \\gruit
System error 53 has occurred.

The network path was not found.

Interestingly, though, NBT does resolve the hostname properly:

C:\>nbtstat -c

Ethernet0:
Node IpAddress: [192.168.73.104] Scope Id: []

                  NetBIOS Remote Cache Name Table

        Name              Type       Host Address    Life [sec]
    ------------------------------------------------------------
    GRUIT          <20>  UNIQUE          192.168.73.152      592

For practical purposes, I don't care about NetBIOS/Samba/etc. on Ubuntu here; I just want my "normal" TCP/IP stuff to work (namely Postgres). Somehow, though, every client on this Windows 10 machine seems to use NetBIOS. If I clear the cache with nbtstat -R, for example, then use some TCP/IP client (e.g. ssh, psql...), the NBT cache immediately shows the Ubuntu hostname and IP address again.

[EDIT: Some commands do not trigger an entry in the NBT cache. nslookup never does. Neither do usual offenders (e.g. ping) when I end the hostname with a dot.]

The real problem, of course, is that despite successfully resolving via both DNS and NBT, I can't actually use the hostnames with any client apps. I've read many conflicting doc pages, blogs, and forum posts about the name resolution order on Windows - and whether the client has a role in determining the resolution method. I'm not sure what's correct / current.

[nslookup behavior in prior edit suggests that the client does have a role in choosing name resolution method. Not sure if it's explicit or incidental - e.g. which of several API functions they happen to call.]

For context:

  • The problem machine is Windows 10; it has no hosts or lmhosts file
  • The Ubuntu machines are 14.04 and 18.04
  • All other Windows machines (all Windows 7) can access the Ubuntu servers by hostname, including for straight TCP/IP services and Samba-type services
  • I've fixed a ton of other stuff throughout this odyssey (e.g. DHCP/DNS reconfig, OS upgrade, anti-malware/firewall upgrades and uninstalls, samba/systemd-resolved reconfig...); the network is in better shape than its ever been, other than this one remaining issue

Any ideas?

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  • Here's an interesting article about the trailing "dot", which I think you know, but not everyone will. It's not very helpful sorry, just interesting.
    – Tim
    Oct 29, 2018 at 7:19
  • That is interesting; I didn't know that about the dot. I only learned enough so far to know that it coaxes Windows into using DNS instead of NBT. I kinda backed into it when testing my DHCP server with a domain name, and wanted to avoid a potential conflict with avahi / .local. Somewhere along the way I read that the dot would suffice on its own, and was able to go back to a blank domain. Thanks for the background!
    – manniongeo
    Oct 29, 2018 at 7:39
  • Did you ever resolve this problem? I believe it's the same problem that many windows10 users have experienced periodically: ip adresses work but host names fail on everything except NSLookup. Nobody has resolved it. Rebooting temporarily cures it but none of the other gazillion suggestions help at all.
    – Craig.Feied
    Feb 4, 2020 at 19:57
  • Unfortunately, no; I've been clinging to Windows 7, due to myriad outstanding Windows 10 issues. Now that 7 is officially unsupported, I'm part-way through upgrading my office, and will probably need to turn attention back to this again at some point.
    – manniongeo
    Feb 5, 2020 at 6:36
  • You can disable NetBIOS in the TCP/IP settings on your network adapter if you really don't need it.
    – lordadmira
    Dec 18, 2020 at 4:02

1 Answer 1

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An error like that happened to me in the past, was a WINS/NBT database corruption error, while the dns resolved correctly.

Restarted the master browser server and it did the trick for me.

A wireshark would probably identify the culprit that reply bad data to the NBT request of your windows 10.

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  • 1
    Found that router (which is also DHCP & local DNS server) is master browser using nbtstat -a for each machine on network, per this article. Rebooted, to no avail :( I'll look at wireshark. Thanks for the suggestions.
    – manniongeo
    Oct 31, 2018 at 1:15

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