[SOLVED] Odd Internal Connections

Mike McCall

Well-Known Member
Reaction score
1,072
Location
Silverton, Oregon
So, after completing a network rebuild you can read about here:

https://www.technibble.com/forums/threads/unable-to-join-domain.63430/

things have been working fine...until recently. I didn't like the fact that my entire office connected through an unmanaged switch to a port on a managed switch directly behind the router. So, since I have a second managed switch I replaced the unmanaged switch in the office with a managed one a month or so ago. Since both the main switch (Meraki) and the secondary switch (Netgear) are auto sensing I didn't use a crossover cable. The network is flat.

Everything seemed to work fine until my wife discovered a problem just the other day. Now her ability to connect to the NAS behind the second switch is sporadically broken. That seems to change by the moment. Her PC is wired directly to a port on the main switch. No connection problems noted prior to just a few days ago.

So, what changed, right? Well, I've been running Zoho for awhile now without issue internally or externally. Having recently read about SplashTop I decided to take advantage of their free offering for up to 10 devices on an internal network just to check out the product. I have the viewer installed on my office PC, and a client installed on my server downstairs, and on my wife's PC - the one I'm having problems with. About the same time I start seeing via the SplashTop viewer that the wife's host is sporadically on a different network preventing me from connecting to it (because SplashTop limits this freebie to a single internal network.). Zoho still connects to all devices properly. Ok, so maybe the two products don't play well together? Maybe, but there's more.

I discovered an oddity in the wired connections of my office PC, wife's PC, and server. (Note that both of these PC's are Win 10 Home and unable to join a domain.) The server says it's connected to: Ad.Dork-SCS.com (fine), office PC to: SCS (also fine), but the wife's PC says it's connected to: Shamrockaudio (not fine). Shamrock Audio was my loudspeaker company which I closed in 2004. The only device that may date back that far is my WNDR3400v2 router. Today all it provides is NAT translation, even WIFI is turned off, though the SSID (not broadcast) is Shamrock. Oddly, her PC can still see my PC behind the second switch in the office, but not the NAS behind the same switch.

I looked at DHCP on the server and noted that a few devices with static ip's in the .1 - .10 range had leases in the .12 - .20 range. I deleted those and noted that I should have left more room for expansion in my ip scheme, though all ip addresses are accounted for and where they should be. That's an issue I can soon address in an upcoming addressing rework.

I may have an equipment upgrade coming soon so a complete network rebuild is on the not-too-distant horizon. I would like to figure this out so whatever mistake I made doesn't get repeated.
 
Hmm, so I'm guessing your setup looks like this:

Internet > Netgear router > Meraki switch > Netgear switch > Computers/Nas

What kind of Netgear switch is it? You say you're not on a domain, so you're workgrouped? You say your wife is connected to an odd network, what was it before? Did the IP address also change? What about DHCP, DNS, gateway, etc? What network are you on, a 192.168.x.x? Subnet?
 
Hmm, so I'm guessing your setup looks like this:

Internet > Netgear router > Meraki switch > Netgear switch > Computers/Nas

What kind of Netgear switch is it? You say you're not on a domain, so you're workgrouped? You say your wife is connected to an odd network, what was it before? Did the IP address also change? What about DHCP, DNS, gateway, etc? What network are you on, a 192.168.x.x? Subnet?

WAN> Netgear Router> Meraki Switch
1.Uplink to router
2.Ooma VOIP
3.Roku
4.Wife's PC
5.Server (basement)
6.Network Printer
7.Meraki AP>Laptop>iPad>Phone
8.Netgear Switch (office)
1.Uplink to Meraki
2.NAS
3.PC
4Mac Mini

16 network devices from 10.58.58.1 - 10.58.58.16.
AP SSID = SCS
Wired Connections: .1 - .10 = static
Server = Ad.Dork-SCS.com
Office PC = SCS
Office Mac Mini = SCS
Wife's PC = Shamrock Audio(?)

Server sees office & wife's PC, and network printer, but nothing else.
Office PC sees everything except Mac Mini
Wife's PC sees office PC & laptop
Laptop sees wife's PC & office PC.

Server = 2012R2
Laptop = Win 10 Pro
Office PC = Win 10 Home
Wife's PC = Win 10 Home
NAS = Synology DS212j
Meraki switch = MS220-8P
Meraki AP = MR18
Netgear Switch = M4100-D10-POE

All devices had proper connectivity until recently. Unable to point to suspicious event beyond what I outlined above. Complete server/network rebuild coming, but would like to find the error so I don't repeat it.
 
Yeah, I initially thought of that but the router is just a gateway with no DHCP & no active wireless. Netgear switch is not a DHCP server either. Synology NAS is not configured as a DHCP server. Only the actual 2012R2 server handles DHCP. Checked that a few times now. It's a good thought though, especially given the reservations I found in the .11+ range on the server for devices with static ip's below .10.

I even thought that maybe there might be something involving Zoho and SplashTop not getting along, but I don't see anything to support that.
 
Is the server an upgraded "descendant" of one that was around at the time or a new clean install? If the Netgear router is the only thing that's that old then it's the obvious place to look; if not then what systems coexisted with that old workgroup? domain? Also, on the 2012R2 server doing DHCP, you can have options set for DHCP at both the address pool level and at the server level I believe - have you checked both places there?
 
Is the server an upgraded "descendant" of one that was around at the time or a new clean install? If the Netgear router is the only thing that's that old then it's the obvious place to look; if not then what systems coexisted with that old workgroup? domain? Also, on the 2012R2 server doing DHCP, you can have options set for DHCP at both the address pool level and at the server level I believe - have you checked both places there?

The "server" is actually a repurposed Dell workstation that's soon to be replaced with a real one. I've had it less than 2-years. I'm guessing on the router's age as I don't recall exactly when I bought it, but it was awhile ago. There's nothing else I have that might date back that far. I'm not sure what you mean exactly about DHCP at two levels.

I think tomorrow I'll take the network down all the way to the modem and reboot everything device by device. Maybe I'll find the problem.
 
In the DHCP setup, you can configure options at the server level ("Server Options") or at the scope level (applying only to that address pool). Not sure which takes precedence if you have something specified in both.
 
In the DHCP setup, you can configure options at the server level ("Server Options") or at the scope level (applying only to that address pool). Not sure which takes precedence if you have something specified in both.

Okay, I got it. No, there's nothing configured under "Server Options." I took the whole thing down like I said and brought each device back up in sequence. No difference. I removed the Netgear switch and went back to the unmanaged switch, no difference. I disabled the Ethernet adapter on the wife's PC and enabled the WiFi adapter as that would put it on the Meraki AP, no difference.

The DHCP scope ranges from 10.58.58.2 - 10.58.58.50, with .2 - .10 excluded from distribution for static ip's. I've turned off ipv6 on all devices.

It's probably staring me in the face and I can't see it.
 
Update (though I don't know what this means):

MaxFocus alerted me to this error on the server (copied from Event ID):

http://eventid.net/display.asp?eventid=4202&source=Microsoft-Windows-Iphlpsvc

Source: Iphlpsvc
Type: Error
Description:
Unable to update the IP address on Isatap interface isatap.{9557A80A-0DB8-4737-8A73-35917D2B8614}. Update Type: 1. Error Code: 0x490
English: Request a translation of the event description in plain English.
Comments:
EventID.Net
From a support forum: "Uninstall network card from devmgmt.msc and reboot system to reinstall network card."

Ok, so I do that and now have two additional events:

http://eventid.net/display.asp?eventid=1041&source=Microsoft-Windows-DHCP-Server

The DHCP service is not servicing any DHCPv4 clients because none of the active network interfaces h...

and...

http://eventid.net/display.asp?eventid=7023&source=Service+Control+Manager

The Intersite Messaging service terminated with the following error: The specified server cannot p...

Should I be looking at the NIC, or maybe the server itself is getting wonky?

Oddly, I've not seen any functional change in the network or device access to the internet.
 
Back
Top