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I just discovered that the SFP ports on the switch are fine. I plugged in another switch to the SFP port, and it works just fine. The issue must be on the server side. I would delete this post, but I can't figure out how to do that...
I recently aquired two used GS752TPS switches. I have them stacked, using the SFP ports 51 & 52. I am trying to connect a new server to the switch stack, and the server has no RJ-45 port, only an SFP port. I made sure there is nothing plugged into port 47 (one of the shared RJ-45 jacks), and plug the direct connect cable from the server into the shared SFP port 47. Nothing happens... No lights, no connectivity. If I leave something plugged into the RJ-45 port when I do that, the light switches from the RJ-45 port to the SFP port, but I still get no connectivity on the SFP port.
What am I doing wrong? Is there a setting in the switch's UI that needs to be changed to "activate" the shared SFP port?
Most SFP+ ports don't allow to fix/lower the speed. Only option would be to install a pure 1G modules and use fiber, not DAC. SFP, SFP+, and fiber does not know anything about speed negotiation - different from plain copper Ethernet.
What server/OS/SFP+ network interface are we faing on the other side?
As per checking, you are trying to connect one of your servers to the shared port or combo port of the GS752TPS. Please make sure that the "Admin Mode" is not disabled on port 47, you may check this under Switching > Ports > Port Configuration. May I know the status of the port 47 on the same page? Does it say Link Down? What is the model number of the module that you are using?
Admin mode is enabled on every single port. The UI shows the port as "Link Down" even though the cable is plugged into the port and the server. I am using a Netgear-compatible SFP Direct Connect cable. It is the same one that I am using to stack my switches. I have tried swapping cables, and that doesn't change anything, so I know the cable is good. The only thing I can think of is an issue with the type of cable for this particular use. Should I not be able to use a Direct Connect cable for connecting a server to the switch?
Model: GS752TPS(B)|ProSAFE 48-Port Gigabit Stackable Smart Switch with PoE and 4 SFP uplinks
I have tried that, on 2 switches in the stack, using all possible shared SFP ports. In fact, I even treod using a different switch entirely (A GS752TP and an FS726T). With those switches, and the same cable, I get link lights when the cable goes from switch to switch, but nothing when it connects to the server.
I think you may have something there... It turns out that the port on the server is, in fact, set to 10G. I have been working with the vendor/Mfg to figure out if it is possible to change the speed to 1G instead. So far, no luck though.
Most SFP+ ports don't allow to fix/lower the speed. Only option would be to install a pure 1G modules and use fiber, not DAC. SFP, SFP+, and fiber does not know anything about speed negotiation - different from plain copper Ethernet.
What server/OS/SFP+ network interface are we faing on the other side?
The server is a SuperMicro box. I am waiting for the vendor to get details from SuperMicro. They have already had me try installing a different NIC driver, but that didn't seem to fix it. In the mean time, I have ordered 1G SFP modules and some fiber patch cables to see if that might make a difference.
