Only 1&1 Dynamic Cloud Servers and 1&1 Dedicated Servers come with a configurable external firewall based on Cisco switches. 1&1 Virtual Servers, 1&1 Managed Servers and 1&1 Shared Hosting packages do not come with a configurable external firewall.
Using the external firewall (configurable through the 1&1 Control Panel), a maximum of 25 rules can be enabled for a rule set. Different rulesets can be created for all of your IPs if necessary.
In addition to a hardware firewall, many operating systems come with pre-installed software firewalls such as iptables for Linux operating systems and the Windows Firewall and IPSEC Service for Windows operating systems. It is also possible to install your own software firewall solution for additional security or in place of one of the above measures.