|Stable release||1.42 (build 5300) / as of August 30, 2006|
|Preview release||2.01 (build 9) / as of August 30, 2006|
|Operating system||Microsoft Windows|
ProtoWall (formerly eWall) is a closed-source freeware program for IP blocking that is similar to PeerBlock. It is designed to block connections from organizations such as MediaSentry, BayTSP and MediaDefender while using peer-to-peer file sharing networks. This application was developed to provide more protection to users than PeerGuardian Version 1 was able to do.
Protowall is a lightweight program that runs in the background, taking up little CPU and memory, while blocking thousands of bad IP addresses. In Protowall, all the work is done by the driver that filters each packet, extracts the IP header and then compares the address with the ones in the table, then either discards or permits the packet to pass. The GUI is essentially a "driver instructor" that communicates to the driver the IP list to check against. The GUI also receives notifications from the driver when a packet arrives and when actions are performed with a packet. Protowall Blocks both inbound and outbound packets. Protowall blocks incoming packets from Internet addresses that are on the Bluetack Blacklists. This is handled by another program called the Blocklist Manager. This program finds and retrieves lists of bad IP addresses. They are sorted (overlapping resolved) and then converted to various formats such as Protowall, PeerGuardian & other common applications and firewalls. 
ProtoWall achieves this via a low-level driver that filters network traffic. It is capable of filtering all NDIS protocols including IPV6 and, most importantly, TCP/IP and UDP – two protocols which are essential for the operation of file-sharing software. The driver sits at a low-level in the system and consequently there is only a small loss of performance when the driver is active.
Although it works in a similar manner, ProtoWall is not a fully featured software firewall and is not suitable for securing a computer from internet-based attacks, however it can be used alongside a firewall without problems.
Unlike similar programs such as PeerBlock and MoBlock, ProtoWall remains closed-source. The creators of ProtoWall state that ProtoWall remains closed-source to "prevent cloning and others stealing its code."