How to turn my laptop into a hotspot?

I have a laptop which is connected to the internet with ADSL modem, and I would like to share the internet for any laptop connecting to wireless router from my laptop using hotspot.

This is what I want:

┌────────────────────┐
│ ADSL modem         │
└───┬────────────────┘
    │
┌───┴───────────────────────┐
│ laptop's wired adaptor    │
│                           │
│ Hotspot software          │
│                           │
│ laptop's wireless adaptor │
└───┬───────────────────────┘
    │
┌───┴──────────────────────┐
│ wireless router(linksys) │
└───┬──────────────────────┘
    │
┌───┴─────────────────────────────┐
│ Laptop computers and cellphones │
└─────────────────────────────────┘

How can I do that?

The purpose of home/consumer routing equipment (I use the term loosely to refer to access points, hubs, switches, routers, modems, and any combination of the above) is to:

• Remove the complexity associated with manually setting up a full-featured, robust and secure network (dedicated equipment, especially for the home, is almost as easy as plug and play)

• Provide reliable configurations designed to work with a wide variety of client devices (or, you know, provide unreliable configurations that only work with that vendor's client devices.... AHEM Linksys I'm looking at you)

• Tightly control the security of the network by providing a hardware firewall on a locked down device where the firewall cannot easily be altered, bypassed or disabled by programs (in other words, if you ONLY ran a firewall on your client computer, it would be riskier than having one on the router, which is a more secure environment due to how restrictive it is)

• Provide better signal reception for wifi, more uptime, and power savings: the routing hardware itself consumes very little energy from the wall socket, especially when compared to the power consumption of a desktop or laptop. Also, the routing hardware provides better signal strength than you can expect from a laptop or desktop, because the shape of the router and the location of the antennae plays a large role in signal strength and reliability. And since the routing hardware uses integrated components that are low-power, active cooling such as fans, which add noise and consume power, are not necessary.

By trying to use computers as a passthrough for your internet connection and sharing that connection with downstream client devices, you lose all of the above benefits:

• You lose the low-complexity factor because configuring a reliable routed network on a computer (regardless of operating system) is worlds more complicated than plugging in a router

• You lose the reliability because rebooting your computer for updates, crashes, etc. is natural, and each time you reboot, any downstream clients lose the connection. Also, you can have programs on your computer taking up all the resources (CPU time, RAM, etc) that can slow your network to a crawl.

• You lose the tight control of the IP-layer security because clever programs can disable your firewall on your computer (especially on an OS such as Windows) but it is much less likely to be possible to compromise a router, especially one running the most up-to-date firmware

• You lose the excellent signal reception of wifi routers, which are tuned to provide longer range broadcasts than most "USB dongles" and PCI-E/Mini-PCIE cards that fit in laptops and desktops

• You lose the power savings, because if anybody wants to use your network from one of the downstream clients, you have to keep the routing PC(s) online and running. If you're routing it through desktops in particular, the power consumption for older-generation video cards and CPUs, even while idle, can be pretty ridiculous.

For these reasons, I think you are asking how to set up a configuration that is just plain inadvisable.

On the other hand, it is possible to manually design your own highly reliable, low-power router using a miniature computer (such as a PandaBoard or a plug PC, a mini ITX, etc). Generally you would run a stable, mature, secure operating system such as OpenBSD or Linux on the device, and you would not use the computer for normal desktop usage, such as playing games, surfing the web, and so on. The device would be "dedicated" to the task of routing. If configured properly, such a device can provide all the benefits of a consumer router, plus adds configurability so that a networking expert can fine-tune the parameters of the routing, such as using a custom Active Queue Management packet scheduling algorithm.

If that's the way you want to go, I think you should educate yourself more about networking technologies and the details of how to configure a reliable routing package on a *NIX box (that is, Linux, BSD, etc). Then you can look into buying a small, low-power device, or build your own and shop for the best-quality network cards, etc. If you make the right decisions along the way, you could be very happy with the result, and it wouldn't be very expensive to do (the operating system software is free, if you use BSD or Linux).

Anyway, that's getting pretty off-topic. The short answer is that I think the best thing for you to do is to not try this. Unless you're up for configuring/building your own dedicated router, the best way to go would be:

<<internet>> --> <<any number of wireless access points, routers, or switches, as you deem appropriate>> --> <<client computers, both desktops and laptops, both wired and wireless>>

Unless you really know what you're doing (and if you did, honestly, you probably wouldn't be asking this particular question on SU), you don't want a computer "in the middle". Especially not a Windows computer that is also in service as an entertainment/productivity desktop computer.

What OS are you on?

• If your laptop has an old wifi adapter or you're using an old OS like XP then you can only create ad-hoc connections. There is no way to create a hotspot in that case. You need to connect the router directly to the ADSL modem
• If your laptop can create a hotspot then just connect other devices to that one, no need to use some router in between. But why use such a complex setup like that when you can connect the router to the modem directly like above? It'll provide better stability and throughput as well as longer range. Besides it doesn't need your laptop to be powered on and running while still allowing other devices to connect to the internet

However if you still really want to create a hotspot from the laptop then the simplest solution is to use some software like Connectify or HostedNetworkStarter to create the hotspot. Some more suggestions:

• customizable (open-source) wifi hotspot software?
• 6 Best Free WiFi Hotspot Software For Windows 10
• Top 7 Free WiFi Hotspot Software For Windows
• 10 Ad-Free Programs to Share Wireless Internet Connection in Windows

Since Vista and up you can also run some commands in Windows to create a hotspot without the need of a 3^rd party software. Just run netsh wlan start hostednetwork to start after setting up with netsh wlan set hostednetwork mode=allow ssid=wifiName key=wifiPassword. Of course it's a little cumbersome if you're not familiar with the command line, but in case you want it that way:

• use “netsh wlan set hostednetwork …” to create a wifi hotspot and the authentication can't work correctly
• How to turn your Windows 10 PC into a wireless hotspot
• Turn Your Windows 10 Computer Into a Wi-Fi Hotspot

On Windows 10 you can even create a hotspot directly from the network settings page