Cannot connect to Internet using CBS110-8T-D

[OK-Koala]

Hey all,

I just received CBS110-8T-D switch and I love everything else, but the fact that one of my computers does not connect to Internet when it is connected to the switch. Let me explain a bit more detail.

I have internet connection which comes to Cisco E4200 Wifi router. Router is set to act as DHCP server for the LAN -ports.

The router works normally and the devices connected to the router get their IP address normally. The router gets both IPV4 and IPV6 addresses from the ISP if that is relevant.

I have two PCs which have network adapters embedded in the motherboard and both PCs are confirmed to be working fine, when connected directly to E4200.

Now I connect these two PCs in the CBS110-8T-D (let's call it switch from now on).

The switch I connect to the E4200.

Having this connection, my PC (let's call it PC1) cannot connect to Internet anymore, where PC2 still can.

Both get IP addresses and the IP address differs.

Diagnosing the PC1 further, it seems to get both IPv4 and IPv6 adress from DHCP. Also, the subnet mask and DNS servers seem to be set correctly for IPv6 and IPv4.

The connection does not work in the Internet nor does it to the internal IP address of the E4200 which acts as the DHCP server. Even PING does not go through.

Again, if I connect the PC1 in the E4200 directly, everything works smoothly.

I tried to disable also the IPv6 on the PC1, but this did not seem to make any difference.

I am using Windows10 Home and it is patched to the latest available version.

The motherboard of the PC1 is ASUS ROG Strix Z490-E Gaming, if that is relevant.

Any ideas how to fix or troubleshoot further would be much appreciated.

[pieterh]

this cisco device is an unmanaged switch Cisco Business 110 Series Unmanaged Switches Data Sheet - Cisco

so here can be no switch config setting that gets in your way !

suggestions are
- faulty cable
- faulty switchport

- Cisco 4200 configuration
  did you by any chance configured the connecting port as DMZ port?

[OK-Koala]

Hi, thank you for your reply.

Unfortunately I could not find the root-cause from your suggestions:

faulty cable: The problem occurs also with different cable combinations and with cables, which work between other device / router.

faulty switchport: I tried with different ports in both 4200 and the Switch, the problem persists with PC1 where with PC2 it works.

4200 configuration: The DMZ is turned off from 4200.

I also tried turning off ipv6 from 4200 and on PC1, still no luck.

I have a gut feeling that this issue would be related in some settings in the NIC of the PC1, but I cannot think what it could be. So far I have tried just setting the link speed from Auto to 1Gbps, 100Gbps full duplex and 10Gbps full duplex, the behavior is always the same.

PC1 gets IP address and other network configuration correctly from DHCP, but even the routers internal IP cannot be pinged.

[OK-Koala · Accepted solution]

Did some troubleshooting last night and I managed to find a solution, but unfortunately the root-cause will remain as mystery.

It seemed that nothing in the Ethernet connection or NIC settings did not help, so I removed the whole ethernet adapter and it's drivers from the device manager of PC1.

After re-installing the adapter device, everything started to work smoothly.

No clue what happened there, but everything is working now so I am happy.

edit:

After a bit of googling it indeed seems to be the interoperability of my NIC and the switch, found this: https://www.reddit.com/r/ASUS/comments/h78ypa/support_rog_strix_z490f_gaming_ethernet_not/g03yb0b/

Quote: "It links to a PDF file from Intel with all of the technical reasons for it, and the lowdown is that it's a 2.5gb connection which requires a different size bit or some **bleep** from your switch/router and if you don't have a router that supports 2.5 the adapter drops down to 1gb connection which apparently causes a problem, it's fixed in the new version of the hardware but for now the new driver apparently fixes it. If you don't already have a router/switch that supports it (they only list like 5 devices total, so you probably don't) then you need the driver."

[tuanluudinh111]

hello,

Is your problem like this, https://community.cisco.com/t5/network-management/sf300-connect-problem/td-p/4302192