Introduction

Smallnet Information Services (SIS) is a server software suite that plays a similar role to Microsoft’s Internet Information Services (IIS), but for protocols in the small internet ecosystem. SIS provides integrated server support for Gemini, Gopher, Nex/NPS, Spartan, Misfin, Scroll, and Titan protocols. Using the built-in SIS Manager interface (accessed via Gemini), administrators can configure and manage multiple virtual servers across different protocols, defining their hostnames, certificates, and protocol-specific settings from a single administrative console.

Request Multiplexing

Incoming connections are multiplexed to each server based on the request’s protocol, SNI and ALPN information, and any information provided within the protocol’s request syntax. Multiplexing allows dynamic server configuration to take effect immediately without server restarts.

SIS uses port listeners to route incoming requests to the appropriate server. This allows for virtual hosting and multiple protocols on one port. However, some protocols have specific restrictions:

  • Nex and Gopher don’t support virtual hosting, so they need dedicated ports
  • Misfin servers on shared ports must use unique hostnames and their own root CA certificates

Since most protocols either use different ports or support virtual hosting, the above restrictions are easily avoided.

Security

SIS implements features that ensure the security of your system:

  • All servers by default rate-limit incoming connections based on IP addresses.
  • There is a global max concurrent connection limit.
  • File permissions are taken into account when serving directories, files, and CGI scripts.

Permissions Under Unix Systems (unimplemented)

SIS will only serve world-readable content; all files and directories must be world-readable. If they are not, they are not served and are hidden from directory listings.

CGI scripts must be world-executable and world-readable to function properly.

Windows Systems (unimplemented)

Like Apache, when SIS is installed as a Windows service, it is ran under a particular user account created for the server. SIS will only serve content readable by this user. CGI scripts must also be executable by this user.

Client Library

SIS can be used as a Golang library to: extend an existing server, build a custom server from scratch, create CGI applications, or implement SCGI application servers. See the section on Using SIS as a Library for more information.