Can anyone confirm that using a persistent outgoing TCP connection on port 80 will not be blocked by the vast majority of consumer firewalls?
That has been assumption based on the fact that HTTP runs over TCP, but of course it is theoretically possible to analyze the packets. Question is do most CONSUMER firewalls do this or not?
HTTP Port-80 is used for HTTP (Hyper Text Transfer Protocol) connection by default. It is a popular and widely used port across the globe. Port 80 was introduced by Tim Berners-Lee in 1991 in the HTTP 0.9 document. The document states that if there is no port assigned for HTTP connection, Port 80 is used by default.
All web traffic, either encrypted or unencrypted, is handled via Port. Generally, port 80 is used for HTTP, and port 443 is used for HTTPS protocol. This article will discuss about the difference between Port 80 (HTTP) and Port 443 (HTTPS) and the steps to enable them on different operating systems.
Port 80 represents the non-secure HTTP protocol, while port 443 is HTTPS, the secure version. Increasingly, Web sites are configured for HTTPS. For a list of common port numbers, see well-known port.
Windows Firewall allows you to restrict outgoing/incoming network traffic for a specific application or TCP/IP port. It is a popular means of restricting network access to/from user workstations or servers.
The feature is called ALG, Application Layer Gateway. This is where the firewall is aware of and perhaps even participates in an application protocol
There are two main reasons a firewall may do this:
ALGs have been a common feature of stateful firewalls for many years, though often the source of instability.
For security proscriptive environments expect HTTP to be validated and filtered either by a firewall or other dedicated policy enforcement appliance.
Residential broadband routers do not tend to have advanced firewall features. I would be surprised to find any with HTTP validation / filtering on port 80.
Personal software firewalls come in two flavours, basic and advanced. Most consumers will have a basic one that probably comes with their operating system and will not do any HTTP validation / filtering.
However, there is a rising trend in antivirus product differentiation of advanced internet content filtering for threat protection, there is significant possibility these may filter HTTP activity (but is difficult to determine with certainty from their Feature Lists).
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