How to register .Net 4.5.1 with IIS8 on windows 10

You can use the dism tool to enable features built into Windows. To install .NET 4.5 (or 4.6, they're the same since it's the same CLR4 underneath) into IIS, I think this will work:

dism /online /enable-feature /featurename:IIS-ASPNET45 /all

The /all flag will include any dependencies so you don't have to figure them all out.

You can also see all of the available features by running:

dism /online /get-features

As an aside, aspnet_regiis was used when you needed to install a version of the CLR into IIS. Since all versions of .NET since 4.0 use the same CLR versions, this is now built into the Windows features. So you use DISM to enable the feature instead.

i do see 4.6 though. Is it same as 4.5.1?

.NET 4.6 is a drop in replacement over 4.5.1. Meaning, your 4.5.1 applications will run on 4.6. So you could say that 4.6 "includes" 4.5.1.

If you're ASP.NET version agnostic and just want the ASP.NET State Service running, Go to IIS -> Web Server (IIS) -> Web Server -> Application Development and choose the latest ASP.NET. This will create ASP.NET State Service in Services.msc which you can then configure to run.