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.
You Might Be Interested in Reading These Articles
Q&A: Mobile App Developers Asked How SeaCat Will Protect Their Apps, Backend, and the Data. Here Are the Answers
We've spent a great deal of time talking to mobile app developers to understand their approach to handling mobile application security. In this Q&A, we put together the answers to the most common questions asked by these app developers.
Published on May 07, 2015
The Outrageous Cost of HTTPS - Why?
Mobile applications use HTTP communication between the application backend and the clients. Because of the demand for higher level of security, IT people implement HTTPS by setting up certificates issued by LetsEncrypt Certification Authority in their application backend server. The shift between non secure HTTP connections to HTTPS connections leads to a significant increase of amount of data being transferred from/to the clients. How is this possible?
Published on June 14, 2016
SeaCat Starter Pack for iOS
Starter pack is SeaCat distribution package that is prepared to enable quick evaluation and understanding how SeaCat product works. Also it is a boilerplate for new mobile applications that are equipped with SeaCat.
Published on April 02, 2015
