What TCP port to use with SeaCat
Introduction
SeaCat requires to specify one TCP port that is eventually used for client-gateway communication. Clients connect to this port to establish TLS channel that is used to exchange requests and related responses. SPDY-based communication protocol is used for traffic in this channel.
SeaCat: Protocol stack
TCP ports reachability
Google performed investigation during WebSocket implementation (late 2009) that showed surprising facts about success rate of client-to-server connections:
- HTTP port 80: 67%
- Custom TCP port (61985): 86%
- HTTPS port 443: 95%
The reason for low HTTP score is that the Internet is today full of proxies and firewalls that are configured to be transparent to HTTP traffic. However, non-HTTP traffic doesn't successfully pass them. Detailed reasoning can be found here: SPDY Essentials presentation from Google at approx. 18th minute of the video.
443 or custom port
SeaCat communication protocol is up to Session layer compatible with HTTPS protocol stack, HTTPS client that connects to SeaCat gateway is politely rejected with no harm on both sides. SeaCat traffic is indistinguishable from HTTPS traffic for intermediates on the network path, and,therefore, it shares the same success rate of connections. For these reasons TCP port 443 is recommended choice for SeaCat.
If for whatever reason you cannot use this port, use any TCP port above 1024 (non-reserved ports). You will likely got little bit worst connection success rate but still useful for practical deployments in common network scenarios.
Need help?
Do you want to review your SeaCat-related design proposal?
Do you have a question we didn’t cover?
Do you want to give some feedback?
Feel free to contact us support@teskalabs.com.
Most Recent Articles
You Might Be Interested in Reading These Articles
From State Machine to Stateless Microservice
In my last blog post, I wrote about implementing a state machine inside a microservice I call Remote Control that will automate deployments of our products and monitor the cluster. Here I would like to describe how all this was wrong and why I had to rewrite the code completely.
Published on February 15, 2023
Don't worry, ASAB and the universe can be fixed
How do my first sprints in TeskaLabs look like? Sheer desperation quickly turns into feelings of illumination and euphoria. And back. I've also made a few new friends and learned a thing or two about flushing metrics. The digital adventure begins.
Published on February 15, 2022
SeaCat Tutorial - Chapter 4: Using MongoDB with REST Integration (iOS)
The previous tutorial introduces several concepts and helps you understand the basic of REST API integration with iOS client written in Swift. There are several limitations, with data storage being the most important. This article provides instructions on how to work around this restriction.
Published on November 25, 2014