@Matan_B 

This could be any of hte following reasons..

1.  The cable is not 100% and only identifying as 100mbps - Cat5e is quite an old cable now, cat 6 should be used.

2.  If the laptop only has a 2.4ghz card, it could well be it only has a 100mbps LAN port. 

Can i ask how if you are only using 2.4ghz (not 5ghz) you are reading over 500mbps connection?    Would you have a picture of this?   WiFi speeds on 2.4ghz dont offer much over 400mbps and even then that is with WiFi6 in a perfect scenario.

@Philbert 

You are right. My network card doesn't support 5GHz, but how can I know the capacity of the lan port?

And I meant on devices who support 5GHz (to prove I do have high network speed) 

@Philbert 

Yes it shows that the speed is 100Mbs.

My network card is Realtek RTL8723BE 802.11 bgn Wi-Fi Adapter (which i checked and support only 2.4GHz), and Realtek PCIe FE Family Controller. 

@Matan_B 

Hey

Yeah that answers the question for you in that case

RTL8723BE 802.11 bgn Wi-Fi Adapter  - Correct this is a 2.4ghz adaptor and supports upto 150mbps over WiFi, however its VERY unlikely you will get anywhere near this on 2.4ghz today.   Expect speeds around 50 / 60mbps

Realtek PCIe FE Family Controller  -  The FE stands for Fast Ethernet, so yes its only a 100mbps LAN connection.

Unless you internet speed is above 100mbps, which is unlikely given the model of VDSL router then that LAN connection is perfectly suitable for you.  The VR600 Router would support 1gbps if you laptop did have this card.

If you wnat faster connections, personally I would recommend looking to a USB 5Ghz WiFi card.   Something like the Archer T4U    https://www.tp-link.com/uk/home-networking/adapter/archer-t4u/

@Philbert 

I see.. Thank you so much! You helped me a lot.