I have uploaded 2 files to uploadfiles.io.
There is a file named STM_Ethernet.zip that is at http://ufile.io/57k7j and a file named LWIP-Ethernet.hex that is at https:/ufile.io/s8kfq.
The zip file contains the source files that I used to make my board work. I haven’t worked with STM32 parts in a couple of years so I won’t be able to offer any help if your board does not work.
If you unzip the file and look in the STMNew/Eth-Test/Src folder, you will see a file named lwip.c. Within that file there is a function named MX_LWIP_Init where the IP address and Netmask are assigned statically. I have them set to 172.16.1.177/255.255.255.0. You can chage the IP address to match your subnet, recompile the code, and program your board.
If you happen to be using a subnet of 172.16.1, you can program you board with the hex file that I built for my board. That file is named Eth-test.hex and is located in the STMNew/Eth-Test/Release folder. You should then be able to ping the board at 172.16.1.177.
The LWIP-Ethernet.hex can be used to verify if your hardware is working. It uses dhcp to obtain an IP address from your network DNS server. If you program your board with the hex file, you will be able to open a webpage by using a web browser to connect to the IP address that the board obtains from your DNS server.
Both hex files assume you are using a STM32F407 processor and a DP83848 Ethernet Phy device.
Good luck with your project.