Highly Performant & Scalable Ultima Online Server Emulator https://www.modernuo.com
Find a file
Kamron Batman 50c8287c7e
refactor(network): move Firewall to UOContent; core keeps only the filter seam
Core now owns the question -- "should this socket be denied?" -- and none of the
answers. The firewall was the last implementation left in core, and the reasons
to keep it did not survive scrutiny: it is not extended downstream, and a shard
running bare core has no way to populate it anyway, since the admin gump and
the commands that mutate it are both content. Larger shards front the server
with an upstream proxy or edge scrubbing and never use it; it survives as the
fallback an admin reaches for over a single player, which is squarely content's
concern.

Nothing about the firewall changes for operators: same Server.Network namespace,
same Configuration/firewall.json, same gump and commands, same legacy .cfg
migration. It reaches the accept path through ConnectionFilters like any other
filter, and registers itself first because an empty set is the cheapest gate.

Untangling core from the firewall entry types first:

- NetworkUtilities built its reserved-network tables out of CidrFirewallEntry,
  which made core depend on the firewall for something with nothing to do with
  banning. Those are constant CIDR blocks answering "is this address in one of
  these ranges?", so they are now a SortedRangeIndex<UInt128> -- the same
  primitive the firewall and blocklist already share. Same semantics, same
  public API, one linear scan replaced by a binary search.
- The CIDR -> normalized range parse those tables needed is now
  IPAddressUtility.TryParseCidrRange, and CidrFirewallEntry drops its private
  copy of that logic in favor of it.

Core no longer references IFirewallEntry or Firewall anywhere. 1344 tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-25 01:18:42 -07:00
.config feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
.github ci: cap job runtime, dump on test hangs, expand the Linux matrix (#2538) 2026-07-16 22:37:06 -07:00
branding feat(build-tool): add application icon and refresh MUO.ico (#2487) 2026-06-14 11:59:54 -07:00
dev-docs refactor(network): move Firewall to UOContent; core keeps only the filter seam 2026-07-25 01:18:42 -07:00
Distribution/Data fix(throwing): grant Str/Dex stat gains for the Throwing skill (#2514) 2026-07-02 23:07:36 -07:00
Projects refactor(network): move Firewall to UOContent; core keeps only the filter seam 2026-07-25 01:18:42 -07:00
tools refactor(network): pluggable accept-path filters; move the blocklist to UOContent 2026-07-25 00:55:42 -07:00
.cursorrules chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
.editorconfig chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
.gitattributes fix: Adds migration checks to CICD, updates dependencies, adds Fedora 37, alpine 3.17 support (#1309) 2022-12-22 12:12:47 -08:00
.gitignore refactor(network): pluggable accept-path filters; move the blocklist to UOContent 2026-07-25 00:55:42 -07:00
AGENTS.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
azure-pipelines.yml chore: Cleans workflows for NodeJS 24 (#2394) 2026-03-28 21:55:29 -07:00
CLAUDE.md feat(network): wire ban channel + blocklist into the accept path; threading policy 2026-07-23 20:38:23 -07:00
CODE_OF_CONDUCT.md Create CODE_OF_CONDUCT.md 2020-05-05 08:51:39 -07:00
CONTRIBUTING.md chore(license): Removes CLA requirement. All contributors moving forward will retain copyright. (#2038) 2024-12-31 02:52:58 -08:00
Directory.Build.props fix: Bumps dependencies. (#2531) 2026-07-14 15:17:55 -07:00
FAQ.md docs: Updates FAQ for time zone issues. (#1368) 2023-03-10 00:18:36 -08:00
GEMINI.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
global.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
LICENSE Fixes more line ending issues (#267) 2020-09-27 13:54:56 -07:00
ModernUO.slnx feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.cmd feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.ps1 fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
publish.sh fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
README.md ci: cap job runtime, dump on test hangs, expand the Linux matrix (#2538) 2026-07-16 22:37:06 -07:00
rider-settings.zip Cleanup/Housekeeping (#242) 2020-09-12 15:31:21 -07:00
Rules.ruleset chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
SPONSORS.md chore: Updates readme files (#2247) 2025-07-27 11:04:32 -07:00
stylecop.json Updates formatting rules (#199) 2020-08-25 18:00:51 -07:00
THIRD-PARTY-NOTICES docs: Adds RunUO-Encryption notice attribution to DarkStorm (#2369) 2026-03-12 23:35:47 -07:00
version.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00

ModernUO - Ultima Online Server Emulator for the modern era!

ModernUO Discord Subreddit subscribers Twitter Follow

Ultima Online Server Emulator for the modern era!

GitHub license GitHub stars GitHub issues
GitHub build Azure Pipelines build

Requirements

Supported Operating Systems

Windows 10/11/2012/2016/2019/2022/2025 MacOS 14+ Debian 12+ Ubuntu 22+ LTS
Alpine 3.22+ Fedora 42+ RedHat 9+ CentOS Stream 9+ AlmaLinux 10 openSUSE 15.6+ SUSE Enterprise 15 SP6 Linux Mint 21+ Arch

Required Frameworks

All Operating Systems

.NET

Windows

VC++ Redistributable v14

Development

git .NET

Supported IDEs

Jetbrains Rider 2025.3+ space VSCode space Visual Studio 2026

Getting Started

  • Install prerequisite requirements
  • Clone this repository (or download the latest):
    • git clone https://github.com/modernuo/ModernUO.git
  • Open ModernUO.sln to start developing

Building/Publishing

Run ./publish.cmd (Windows) or ./publish.sh (Linux/macOS) with no arguments to launch the guided build tool. It will:

  • Check prerequisites (.NET SDK, native libraries)
  • Walk you through configuration and platform selection
  • Build and publish the server to the Distribution directory
  • Show deployment instructions for cross-compiled builds

Command Line

./publish.cmd [release|debug] [os] [arch]

Linux Prerequisites

Fedora, CentOS, RHEL, AlmaLinux, Rocky, etc

dnf upgrade --refresh -y
# RHEL-family distributions (CentOS Stream, AlmaLinux, Rocky, RHEL) need CRB and EPEL enabled.
# Fedora skips this block.
dnf install -y dnf-plugins-core
dnf config-manager --set-enabled crb
dnf install -y epel-release
# Prerequisites
dnf install -y findutils libicu libdeflate-devel zstd libargon2-devel liburing-devel

Ubuntu, Debian, etc

apt-get update -y
apt-get install -y libicu-dev libdeflate-dev zstd libargon2-dev liburing-dev

OSX Requirements

brew install icu4c libdeflate zstd argon2

Running the Server

  • Follow the publish instructions
  • The Distribution directory is portable — copy it to your production server for deployment
  • Run ModernUO.exe or dotnet ModernUO.dll from the Distribution directory
  • On first run, the server will prompt you to configure game data file locations

Troubleshooting / FAQ

Want to sponsor?

Thank you for supporting us! You can find out how by visiting the sponsors page.

Collaborators

Kamron Batman Mark1145

Thanks

  • RunUO Team & Community
  • Voxpire, the ServUO Team & Community
  • Karasho, Jaedan and the ClassicUO Community



Development Tools & Plugins provided with ♥ by

JetBrains
Material Theme

Code Signing Policy

Free code signing provided by SignPath.io, certificate by SignPath Foundation.

This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it

Teams & Roles

Approvers & Committers: Development Team