There are some hosting packages offering 1gbps, is there some tools or available resources to check if my connection are on a gigabit line? I want to check on a Linux server though.
For a web hosting package, there will not have difference between 100Mbps and 1Gbps, because the performances will depend on the amount of websites on the same server.
But you can download the speedtest mini tool and make a speedtest from a server with 1Gbps to check the speed.
Create a 5 GB file for testing purposes (yourdomain.com/5GB.iso) and download it from somewhere else where you have a gigabit connection.
if the download speed is + 13 MB/s, you are on a + 100 Mbps connection.
you could also be on a 1 Gbps connection but with limited upload speed.
Unfortunately, without Root SSH you aren't able to check the network port speed, but you can do a wget test from server to server to check whether 100MB or 1GB as other members mentioned above.