.NET CVS Library (NetCvsLib)
- A CVS client library written entirely in C# for the .NET platform. It is implemented as an assembly, and thus can easily be incorporated into other projects. [LGPL]
- http://sourceforge.net/projects/sharpcvslib/

ComponentScience TransPort
- A serial and Winsock communications library for the Microsoft .NET Framework. Includes support for X-, Y-, and Z-Modem.
- http://www.componentscience.net/elements/transport/

edtFTPnet
- A FTP client library written in C# for .NET applications. [Open source, LGPL]
- http://www.enterprisedt.com/products/edtftpnet/overview.html

dotEtiveSocket
- A derivate of the original Socket. It compatible with Socks 4, 4A, and 5.
- http://www.etive.com/software/dotEtiveSocket/

dotEtiveFTP
- Transfer, rename, delete, make, enumerate files and folders synchronously and asynchronously. It supports Socks 4/4A/5, IPv6, transfers resuming, recusive folder transfer, custom commands, transfers tracking, and FXP data transfer for faster backups.
- http://www.etive.com/software/dotEtiveFTP/

Rebex Time.NET
- A SNTP/NTP time synchronization library for .NET and .NET Compact Framework. By Rebex.
- http://www.rebex.net/time.net/

Devshock .NET SmppClient
- A component was designed to provide support for any kind of application oriented to the SMS environment.
- http://www.devshock.com/products/protocol/smppClient/

Devshock .NET SockServer
- A library for socket server applications.
- http://www.devshock.com/products/net/SockServer/

Devshock .NET SockClient
- A library for socket client application.
- http://www.devshock.com/products/net/SockClient/

Who Is .NET
- Lookup domain name registration and other information. By ComponentSpace.
- http://www.componentspace.com/whois.aspx

Trace Route .NET
- Perform Internet route tracing to determine network delays and topology. By ComponentSpace.
- http://www.componentspace.com/traceroute.aspx

Internet Time .NET
- Retrieve the date and time from NTP time servers. By ComponentSpace.
- http://www.componentspace.com/internettime.aspx

ICMP .NET
- Send ICMP echo messages and receive echo replies. By ComponentSpace.
- http://www.componentspace.com/icmp.aspx

DNS .NET
- Query DNS servers for MX and all the other resource record types defined by RFC-1034 and RFC-1035. By ComponentSpace.
- http://www.componentspace.com/dns.aspx

FTP for BizTalk Server
- Configure a BizTalk Server Message Port to use the FTP Application Integration Component (AIC) and upload BizTalk Server messages to an FTP server. By ComponentSpace.
- http://www.componentspace.com/ftpbts.aspx

FTP .NET
- FTP client functionality. By ComponentSpace.
- http://www.componentspace.com/ftp.aspx

AlertPOP .NET
- Non-intrusive popup messages similiar to MSN Instant Messenger and Yahoo Messenger.
- http://www.componentdesigns.com/products/alertpop.asp

ComponentSpace .NET Internet Suite
- Consists of over 150 classes covering the most popular Internet protocols and includes DNS, FTP, ICMP, NTP, SMTP Email Checker, Trace Route and Who Is components. [Commercial]
- http://www.componentspace.com/internetsuite.aspx

DeepakChitnis DnsMX
- A .NET component resolve the mail servers of any given domain using the MX record of the DNS System.
- http://www.deepakchitnis.com/Products/DnsMX.aspx

wodSFTP.NET
- Transfer data securely over SSH layer using AES, DES, and BLOWFISH encryption. By WeOnlyDo! Software. [Commercial]
- http://www.weonlydo.com/index.asp?showform=SFTP.NET

wodSSH.NET
- Client side .NET component for Telnet and SSH protocol. By WeOnlyDo! Software. [Commercial, open source]
- http://www.weonlydo.com/index.asp?showform=SSH.NET

Genuine Channels
- Use bidirectional non-blocking GTCP, GHTTP, Shared Memory and GUDP channels with IP multicasting support.
- http://www.genuinechannels.com/

aspNetMime
- Parse MIME and Email messages. Decodes quoted printable, MIME body parts, and email properties. Stream email body parts to ASP.NET webpages. By Advanced Intellect.
- http://www.aspnetmime.com/

aspNetDns
- Perform DNS lookups. Includes synchronous and asynchronous method calls. By Advanced Intellect.
- http://www.aspnetdns.com/

Sax.net Communications
- Serial Communications Library for the Microsoft .NET Framework.
- http://www.sax.net/framework/communications/

Rebex FTP.NET
- Communicate with any FTP server in your .NET programs. Sync, Async and all common proxy servers supported.
- http://www.rebex.net/ftp.net/

FirstFloor.MSN
- Msn Messenger object model for the .NET platform.
- http://www.1stfloor.nl/

ABCUpload .NET
- ASP.NET file upload component with progress bar and file corruption auto-fixing. Unicode and MacBinary compatible. By WebSupergoo.
- http://www.websupergoo.com/abcupload.net-1.htm

Smilla .NET Communication Library
- An NNTP protocol library written in C# and distributed under the terms of the GNU Lesser General Public License.
- http://www.smilla.ru/

PowerTCP .NET
- TCP components for .NET, including FTP, mail, SSL and Telnet. By Dart Communications, Inc.
- http://www.dart.com/dotnet/

IP*Works! .NET Edition
- A collection of more than 30 IP networking components written in C#, including HTTP, SMTP, Whois, SOAP and Telnet. By /n software, Inc.
- http://www.nsoftware.com/products/showprod.aspx?part=IPN5-A