 }}){kind=logo}
14 | 
3 | 
10 |
11 | Unlike traditional network impairment tools that target backbone network quality between servers and switches, NetHang is optimized for:
12 |
13 | - Simulating network quality from user equipment (UE) to servers, typically traversing:
14 | - UE <--> Lan (Wi-Fi or Wired) <--> Routers <--> ISP edge nodes <--> APP servers
15 | - UE <--> Cellular <--> ISP edge nodes <--> APP servers
16 | - UE <--> Air interface <--> Satellite <--> APP servers
17 |
18 | 
19 |
20 | - The current network model is built and simplified based on existing network quality data modeling, while also supporting users to easily customize the network models they need for testing in YAML format.
21 |
22 | - NetHang clearly displays the differences in data traffic before and after simulation, as well as the state of the simulation conditions.
23 |
24 | 
25 |
26 | ## Features
27 |
28 | - Traffic rate limiting and shaping
29 | - Network latency and latency variation simulation
30 | - Packet loss simulation
31 | - Support for both uplink and downlink traffic control
32 | - Configurable traffic rules and models
33 | - Real-time traffic statistics display
34 |
35 | ## Requirements
36 |
37 | - Python 3.8 or higher
38 | - Linux system with `tc` and `iptables` support
39 | - Root privileges for traffic control operations
40 |
41 | ## Installation
42 |
43 | ### From PyPI (Recommended)
44 |
45 | You can install NetHang from PyPI using the following command:
46 |
47 | ```pip install nethang```
48 |
49 | ### From Source (For Developers)
50 |
51 | You can also install NetHang from source by cloning the repository and running the following command:
52 |
53 | ```pip install .```
54 |
55 | ## License
56 |
57 | MIT License
58 |
59 | Copyright (c) 2025 NetHang Contributors
60 |
61 | Permission is hereby granted, free of charge, to any person obtaining a copy
62 | of this software and associated documentation files (the "Software"), to deal
63 | in the Software without restriction, including without limitation the rights
64 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
65 | copies of the Software, and to permit persons to whom the Software is
66 | furnished to do so, subject to the following conditions:
67 |
68 | The above copyright notice and this permission notice shall be included in all
69 | copies or substantial portions of the Software.
70 |
71 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
72 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
73 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
74 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
75 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
76 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
77 | SOFTWARE.
78 |
79 | ## Contributing
80 |
81 | 1. Fork the repository
82 | 2. Create a feature branch
83 | 3. Commit your changes
84 | 4. Push to the branch
85 | 5. Create a Pull Request
86 |
87 | Please make sure to update tests as appropriate and adhere to the existing coding style.
88 |
89 | ## Authors
90 |
91 | NetHang Contributors
92 |
93 | ## Acknowledgments
94 |
95 | - Thanks to all contributors who have helped with the project
96 | - Inspired by various network traffic control tools and utilities
97 |
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7 |  }}){kind=icon}
17 | A web-based tool for simulating network quality
19 |© 2025 Hang Yin. All rights reserved.
46 |Licensed under the MIT License
47 |
211 | NetHang is a web-based network quality simulation tool that allows you to create and manage 259 | network paths between LAN and WAN interfaces. Ideal for use 260 | with software routers on Linux platform. It focuses on simulating weak network (poor network) 261 | conditions, with built-in scenario models(Edge, 3G, 4G, Wi-Fi, Starlink, etc.) and combinations of 262 | parameters such as packet loss, delay, jitter, and bandwidth limitation, etc. It helps you 263 | simulate various network conditions and monitor their effects on traffic.
264 |
267 | How NetHang looks like:
271 |
274 | In simple terms, NetHang needs to run on a Linux-based software router. If you already 282 | have such 283 | a software router device or are familiar with how to set up the environment, it will be very 284 | convenient.
285 |If not, please follow the instructions below step-by-step to build one. Depending on your 286 | hardware and network environment, you may encounter different issues, which we can discuss and 287 | troubleshoot on GitHub.
288 |A Ubuntu 22.04 LTS server (or desktop) with at least TWO network interface cards (NICs) is 290 | required.
291 |
294 | 302 | 307 |
308 |To install the required packages, run the following command:
312 |sudo apt update; sudo apt install iproute2 iptables libcap2-binCheck command paths:
314 |which tc; which iptablesThey are typically located in /sbin/tc and
316 | /sbin/iptables (or /usr/sbin/tc and
317 | /usr/sbin/iptables).
318 |
Grant the CAP_NET_ADMIN capability, which is required for tc and
320 | iptables:
sudo setcap cap_net_admin+ep /usr/sbin/tc; sudo setcap cap_net_admin+ep /usr/sbin/xtables-nft-multiVerify the permissions:
323 |iptables -Ltc qdisc add dev lo root netem delay 1ms;tc qdisc del dev lo rootIf the output are without errors, the permissions are set correctly.
326 |If not, you may need to reboot the machine.
327 |334 | 339 |
340 |Before proceeding, check whether IP forwarding is currently enabled on your 345 | Ubuntu machine:
346 |cat /proc/sys/net/ipv4/ip_forwardIf the output is 0, IP forwarding is disabled. If it's 1, it's already enabled. 348 |
349 | 350 |To enable IP forwarding temporarily (valid until the next reboot), run:
352 |sudo sysctl -w net.ipv4.ip_forward=1To make the change permanent, edit the /etc/sysctl.conf file and
354 | uncomment or add the line:
net.ipv4.ip_forward=1Then, apply the changes:
357 |sudo sysctl -p /etc/sysctl.conf365 | 370 |
371 |Identify your network interfaces using the ip command:
376 |ip addrYou should see a list of interfaces like eth0, eth1, etc.
378 | 379 |Edit the network configuration files for your interfaces. For example, to
381 | configure eth0 and eth1, you'd edit /etc/network/interfaces:
sudo vi /etc/network/interfacesHere's a sample configuration for eth0 and eth1:
384 |# eth0 - Internet-facing interface
385 | auto eth0
386 | iface eth0 inet dhcp
387 |
388 | # eth1 - Internal LAN interface
389 | auto eth1
390 | iface eth1 inet static
391 | address 192.168.1.1
392 | netmask 255.255.255.0Apply the changes to network interfaces:
396 |sudo systemctl restart networking404 | 409 |
410 |To enable NAT for outbound traffic from your LAN, use iptables:
414 |sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADEMake the change permanent by installing iptables-persistent:
416 |sudo apt update
417 | sudo apt install iptables-persistentFollow the prompts to save the current rules.
419 |426 | 430 |
431 |This step is optional. If you want to use DHCP to assign IP addresses to devices 435 | on the LAN, you can configure the DHCP server.
436 | 437 |If you want your Ubuntu router to assign IP addresses to devices on the LAN, 439 | install the DHCP server software:
440 |sudo apt update
441 | sudo apt install isc-dhcp-serverEdit the DHCP server configuration file:
445 |sudo vi /etc/dhcp/dhcpd.confHere's a sample configuration:
447 |subnet 192.168.1.0 netmask 255.255.255.0 {
448 | range 192.168.1.10 192.168.1.50;
449 | option routers 192.168.1.1;
450 | option domain-name-servers 8.8.8.8, 8.8.4.4;
451 | }Start the DHCP server:
455 |sudo systemctl start isc-dhcp-serverTo ensure the DHCP server starts at boot:
459 |sudo systemctl enable isc-dhcp-serverYou can install NetHang from PyPI using the following command:
470 |pip install nethangYou can also install NetHang from source by cloning the repository and running the following 473 | command:
474 |pip install .Starting NetHang is very simple. Just run the following command:
477 |/path/to/nethang
481 | NetHang will running on port 0.0.0.0:9527 by default. You can access the website by any browser.
485 |
488 | You can login with the default username and password: admin.
Then you can start to use NetHang.
493 |
496 | 
504 | Pre-configured network models that simulate common network 513 | conditions.
514 |Configure specific network parameters:
532 |A path represents a connection between your User-Equipment (UE) and the Application Services. 547 | Each path can be 548 | configured 549 | with:
550 |TCP, UDP, or IP
556 |Source and destination IP addresses
564 |Port numbers (for TCP and UDP)
572 |
579 | Models are pre-configured network paths that simulate common network conditions.
587 |
590 | You can customize the network settings for each path.
597 |
600 | The application provides real-time monitoring of network conditions through three charts:
608 |Shows the bit rate for both uplink and downlink traffic. 614 |
615 |Displays the number of packets in the queue.
623 |Shows the packet loss rate over time.
631 |
638 | More models to choose from.
652 |Debian, OpenWRT, etc.
660 |Support recording statistics to a file or database.
668 |Frame overhead size, Jitter distribution, Packet loss 676 | distribution, Rate limit burst size & ceil rate. etc.
677 |688 | 692 |
693 |NetHang is a tool for simulating network conditions in a controlled environment. 697 | It allows you to test your network applications under various network 698 | conditions.
699 |