In most residential service, the ISP configured the modem to provide a single public IP address. Besides serving as the point of connection to the modem, a router serves a few critical purposes:
Provides a firewall to protect your network from malicious intrusion attempt from the Internet
Provides the needed DNS and DHCP services to devices on your network that allows them to have an IP address and the ability to find external sites
Manages the IP address translation and routing required to allow all of your network devices use
a single public IP address
If you connect your modem directly to a switch that connects to your network, the first device that requests an IP address will get the single available IP address and none of the others will get a usable IP address and as a result, will not be able to access the Internet. They also will be lacking the services provided by a router as listed above.
In most residential service, the ISP configured the modem to provide a single public IP address. Besides serving as the point of connection to the modem, a router serves a few critical purposes:
Provides a firewall to protect your network from malicious intrusion attempt from the Internet
Provides the needed DNS and DHCP services to devices on your network that allows them to have an IP address and the ability to find external sites
Manages the IP address translation and routing required to allow all of your network devices use a single public IP address
If you connect your modem directly to a switch that connects to your network, the first device that requests an IP address will get the single available IP address and none of the others will get a usable IP address and as a result, will not be able to access the Internet. They also will be lacking the services provided by a router as listed above.
Please get a router!