Network issues

I know that we have to have some computer nerds in here that know more about networking than I do. Here’s the problem:

Two desktops, one laptop, all running the latest Win 10, all on the same workgroup. File/printer sharing enabled.

About three weeks ago, they stopped talking to one another. I can see the computer names in my network list. I can open a cmd box and ping another computer successfully. But if I try to map a drive or open one of the other computers, it says WINDOWS CANNOT ACCESS \FRONTDESK (or any other name). I’ve tried connecting with IP address. I’ve tried putting the names and IPs in C:\Windows\System32\drivers\etc\hosts.

Running network diagnostics is useless. It basically comes up and says yeah, you can’t connect, buh-bye.

I’m at my wit’s end. I have been researching this for weeks. I’ve tried everything that I see suggested and I still can’t use my network. I’ve done everything except sacrifice a chicken on the keyboard and I think that’s next.

Has anyone had this problem and if so, what did you do to fix it? Thanks in advance!

Have you rebooted your router?
Are you using a wired connection or Wifi?
Are you using Windows Firewall or a third party firewall?

Can you PING by name?

Are the IP addresses of the form 169.254.x.x? If so you have problems.

Which box (if any) is acting as DNS server? Do you have a DHCP server? Can you list the output of IPCONFIG /ALL ?

Try the following on all boxes:
IPCONFIG /FLUSHDNS
NBTSTAT -RR (the -RR is case sensitive)

What happens if you stop the firewall?

Ok, so you say you can ping the other devices. Can you ping their names? i.e., if you have a computer named ‘computer’, what happens when you type ‘ping computer’? Do you get a ping back or something that says ‘ping request could not find host computer’ or some other message indicating a fail? If you are unable to ping the name of the host, whatever it is, then the problem is (probably) DNS and you basically just need to flush your DNS cache. The syntax is ‘ipconfig /flushdns’ for a windows 10 box. If you can ping the host name, then the only other thing I can think of is it’s a WINS or related issue. You might also check to see what your gateway is, though honestly if they are on the local subnet it shouldn’t matter.

I’m assuming you don’t have an actual windows domain or a server (if so, then the problem might be the way the client is cached…in which case you can remove the client from the domain and then re-authenticate). If you do have a windows server then post that and I could probably figure out what’s up with that, even though I’m not a systems guy.

You may be able to narrow down what computer is having the issue by simply directly connecting them (with a switch or a crossover cable) and using SSH. It will either prove or rule out router/DNS issues. Check services.msc (type in ‘RUN’ box or cmd) and group policy management to make sure the services you are using or need are enabled on the computers in question. Just a starting point. Hope it helps. I’m more of a hands-on guy.

I’ve rebooted everything, including the router, numerous times.
The desktop computers are wired. The laptop is wifi.
Windows Firewall. I’ve turned it off and tried, no joy.
I can ping by name and IP address both.
The IP addresses are all 192.168.1.xxx
I’ve done flushdns and nbstat
IPCONFIG/ALL on the Office computer shows
Windows IP Configuration

Host Name . . . . . . . . . . . . : Office
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : wp.comcast.net

Ethernet adapter Ethernet:

Connection-specific DNS Suffix . : wp.comcast.net
Description . . . . . . . . . . . : Realtek PCIe FE Family Controller
Physical Address. . . . . . . . . : 40-A8-F0-5F-69-64
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2603:300c:113:4ef0:49a6:b763:3232:d7a4(Preferred)
Temporary IPv6 Address. . . . . . : 2603:300c:113:4ef0:bc5e:f9dc:fe4:3bb3(Preferred)
Link-local IPv6 Address . . . . . : fe80::49a6:b763:3232:d7a4%11(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.102(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Monday, June 5, 2017 7:13:51 PM
Lease Expires . . . . . . . . . . : Tuesday, June 6, 2017 7:14:14 PM
Default Gateway . . . . . . . . . : fe80::1691:82ff:fe34:d387%11
192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 88123632
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1B-7C-4D-6C-40-A8-F0-5F-69-64
DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled
Connection-specific DNS Suffix Search List :
wp.comcast.net

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:3cd6:385f:3f57:fe99(Preferred)
Link-local IPv6 Address . . . . . : fe80::3cd6:385f:3f57:fe99%10(Preferred)
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 134217728
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1B-7C-4D-6C-40-A8-F0-5F-69-64
NetBIOS over Tcpip. . . . . . . . : Disabled

Okay, you have your router acting as a DHCP server and a DNS server. This is good. Your DHCP lease time is one day. This is not good. You should change it to a week or more.

That Connection-specific DNS suffix looks wrong, so take a look at the DNS and DHCP servers on your router to see where it’s applied. I’m wondering if your workstations are trying to resolve names via Comcast’s DNS servers which, of course, know nothing about your network.

If you change the DNS server remember to clear the local caches as I described above. If you change the DHCP server, run IPCONFIG /RELEASE then IPCONFIG /RENEW.

Have you tried removing all the computers from the HomeGroup and then recreating it?

Good one. Are you running a Homegroup or a Workgroup? The two are different.

And is your Workgroup or Homegroup named wp.comcast.net? Because that’s a seriously bad move.

Might help if it’s a WINS issue or the home equivalent of a trust relationship issue. Can’t hurt.

I noticed that the default gateway is set to a MAC address, which is interesting…it should just be the router that is giving out the DHCP and DNS addresses. Since we’d need to see what the ethernet MAC is on the router, can only guess that it’s the same…if not then that might be the issue there.

[QUOTE=Quartz]
And is your Workgroup or Homegroup named wp.comcast.net? Because that’s a seriously bad move.
[/QUOTE]

No, it’s pointing to an external host for DNS…wp.comcast.net is presumably Comcast’s DNS host (assuming the OP is using Comcast as their ISP).

Nah, that’s the IPv6 address and the IPv4 address wrapped to the next line.

Not necessarily. Where I used to work we had leases set at one hour. A contractor talked my boss into changing it to 48 hours. I told him that was probably not a good idea. I was right, because the nature of our setup was that we had a lot of what I called “drive-by” traffic. Someone might be in or near one of our buildings (our network covered 4 buildings) for just a few minutes and maybe not even actually do anything, just connect. That IP was then tied up but idle for two days, causing us to to quickly use up all our available IPs.

Result: lots of people were unable to get online that had important work to do. That was around the time that Apple, in their infinite wisdom, decided to remove the ability to terminate a lease from the server side, so it took nearly two days for our network to become usable again.

Utilizing non-routable internal IPs fixes this problem. You can’t run out of IPs so long lease times are great, especially for logging and auditing purposes.

Let me change the lease. I’ll post results.

Workgroup, with the default name of Workgroup. I’ve been burned badly by homegroups in the past, so not inclined to use them now.

We are.

Indeed, but this is for home use, not work.

Set your DHCP server to give a suffix of .home or similar

Quartz, I decided to leave the lease at one day. We haven’t diddled with the router since installation and I am inclined to leave it alone for the moment.

Actually, this is my work environment. This is the setup for my Taekwondo school.

Okay, so something - likely your DHCP server - is supplying a Comcast DNS suffix and I expect that’s the problem, BICBW.