Hi, the DE1-SoC only has an Ethernet PHY connected to the HPS EMAC, as such, even if the FPGA can support an MAC IP, there is no PHY that you can hook up to. Unless of course, you use expansion card that utilizes the GPIO expansion header on the FPGA. If you are not using the HPS for any other purpose except just to read back the data, you can opt for boards such as the Max 10 (http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=218&no=998) that has the Ethernet PHY on the FPGA side.
The downside is you will need to regenerate the Linux portion of the design, but thankfully there is a guide for this specific board located here:
https://rocketboards.org/foswiki/view/documentation/alteramax1010m50revcdevelopmentkitlinuxsetup