I've been trying to get a new MX250 working with a copper SFP for the WAN port. When I plug in a MA-SFP-1GB-TX and other end into a 3750X, all I get the link light going on and off and on and off so on. Nothing is logged in syslog on the switch.
If I put in another generic SFP, I don't get a link light at all, again nothing is logged. So I tried a Cisco branded SFP and with that one I get a link light and all seems ok. But if I reboot the MX250, the link light doesn't come back on and the MX250 is unreachable. Oddly on the switch I have a link light. To get it working, I have to reinsert the SFP a few times and all seems ok again.
The weird part is, if I insert any of these SFP's into the SFP section (ports 11-18) of the MX250, they all show up a link light straight away.
So which SFP will work reliably in the Internet port?