As the question asks "Can DHCP be effected by a network switch?". Everything in my mind says NO but here is the situation.
Small business/office. Comcast Business internet. Using Comcast gigabit router/switch. 5-Windows 10 Desktops, various cameras, printers, etc. Customer contacts me that one of their desktops suddenly can't connect to certain websites (e.g. main AOL page works but get 404 errors trying to get email). I spent a bit of time troubleshooting and determined it is not getting an IPV4 IP address via DHCP. What is strange is that if IPV6 is active, they can get to some places. Once I deactivated IPV6, nothing works at all. I tried a bunch of things (assigning 8.8.8.8/8.8.4.4 for DNS), but still not really usable. I tried resetting all networking, uninstall/reinstall the NIC numerous times, tried using my own USB NIC device, etc. Everything was still wonky.
So, I assigned a fix IP address using the Comcast 10.1.10.x pre-configured range and now everything works. I manually updated Windows 10 the the latest. Updated Malwarebytes and ran a full scan, which found a Trojan of some kind. Cleaned it off, ran full Defender scan, etc. All seemed good with the fixed IP address so I left it at that until I had more time to figure out why DHCP wasn't working.
Then they called me the next day saying they can't print?. They use an HP 87xx series printer connected to their network. So I check it and it too can't get an IP address via DHCP.? Did I mention everything else in this office is working just fine? So I gave the printer a fixed IP address and suddenly the 20-documents backlogged from this desktop start printing.
Again, this makes no sense until I considered this. Both the printer and the desktop are connect to the Comcast router/switch/network through a small 8-port gigabit switch (i.e. Comcast-->Netgear 8-port switch-->Desktop and Printer having issues). Yes I tried resetting it. All lights say everything is working and when it comes to basic connectivity, everything plugged into this switch work - except for getting a DHCP address?
So before I go back to the client to swap out this switch (I hate problems that, while I have a workaround, don't have a true answer or solution), is it possible for this switch to cause DHCP issues? This setup has been working just fine for many months (they recently moved into this new building).
Small business/office. Comcast Business internet. Using Comcast gigabit router/switch. 5-Windows 10 Desktops, various cameras, printers, etc. Customer contacts me that one of their desktops suddenly can't connect to certain websites (e.g. main AOL page works but get 404 errors trying to get email). I spent a bit of time troubleshooting and determined it is not getting an IPV4 IP address via DHCP. What is strange is that if IPV6 is active, they can get to some places. Once I deactivated IPV6, nothing works at all. I tried a bunch of things (assigning 8.8.8.8/8.8.4.4 for DNS), but still not really usable. I tried resetting all networking, uninstall/reinstall the NIC numerous times, tried using my own USB NIC device, etc. Everything was still wonky.
So, I assigned a fix IP address using the Comcast 10.1.10.x pre-configured range and now everything works. I manually updated Windows 10 the the latest. Updated Malwarebytes and ran a full scan, which found a Trojan of some kind. Cleaned it off, ran full Defender scan, etc. All seemed good with the fixed IP address so I left it at that until I had more time to figure out why DHCP wasn't working.
Then they called me the next day saying they can't print?. They use an HP 87xx series printer connected to their network. So I check it and it too can't get an IP address via DHCP.? Did I mention everything else in this office is working just fine? So I gave the printer a fixed IP address and suddenly the 20-documents backlogged from this desktop start printing.
Again, this makes no sense until I considered this. Both the printer and the desktop are connect to the Comcast router/switch/network through a small 8-port gigabit switch (i.e. Comcast-->Netgear 8-port switch-->Desktop and Printer having issues). Yes I tried resetting it. All lights say everything is working and when it comes to basic connectivity, everything plugged into this switch work - except for getting a DHCP address?
So before I go back to the client to swap out this switch (I hate problems that, while I have a workaround, don't have a true answer or solution), is it possible for this switch to cause DHCP issues? This setup has been working just fine for many months (they recently moved into this new building).