IP-based solutions

An overview of some of the most popular file transfer methods is available from WinSCP's protocols page.

[#bittornt]: BitTorrent

BitTorrent is the name of some software that uses a protocol which is itself also called BitTorrent.

Although the software called BitTorrent uses "TCP ports, BitTorrent does not use UDP", some other clients may support using UDP.
BitTornado: TheSHAD0W's Experimental BitTorrent Client

For Windows, and more. (Uses Python.) Source available. (Wikipedia's page on BitTornado identifies the software license as the “MIT License”.

With this client, quoting the BitTornado FAQ:

Note that a file is not complete until it says "done"; "100%" is not good enough.

When the software opens, click on the “Prefs” (underlined blue hyperlink, near the upper-right corner of the main window) to configure some preferences. For instance, check “Initiate and receive connections via IPv6” if that is desired. (Then, click “Save”, and restart BitTornado, as the change won't take effect until doing so.)

Although the FAQ says to listen to TCP ports above 6881, the program seems to show default ranges of 10000 through 60000. This is true in the Microsoft Windows version (seen on the Prefs box), and maybe other platforms too (indicated by fffanatics's answer to his own StackOverflow question which mentions BitTornado). Forum post says, “For newer updates of tornado you need to open the ports it shows, the numbers are changable.”


BitComet had a really neat feature, which is working when other clients didn't. The torrent had pointed to some Japanese filenames which weren't usable on my local operating system, and BitComet intelligently changed the invalid characters to underscores instead of question marks, since underscores were supported by my local machine's file system and question marks weren't. BitTornado, Vuze, and I think utorrent all failed to do the job right. Then again, I wouldn't necessarily say it was more masterfully-designed software all-in-all, because BitComet did have some memory eating issues that caused it to keep crashing. Still, I could then start it up again and make some progress, unlike the other software with which I couldn't even do that. An advertisement would display on the right panel. I believe it is closed source. This program somehow became the default download manager for Firefox downloads (when it was running, anyway).

BitTornado's Shad0w has blocked BitComet due to the BitComet code base being uncooperative, apparently with a torrent community's attempts to discriminate, favoring those who upload more.

µTorrent (often called uTorrent)
A fairly small application, this product's download page cites support for Wine and versions of Windows ranging from Windows 95 (with Winsock 2 Update), Windows 98, Windows NT, up through Vista. As of January 13th, version 1.7.5 was the latest released version, but there was also a post on forum.utorrent.com with links to a download of an alpha for 1.8.
Azureus / Vuze Java BitTorrent Client
Uses Java
BitTorrent.Com's Download page

This may come with BitTorrent DNA, a website download accelerator which installs a Control Panel applet called DNA and an entry called DNA in the Microsoft Windows operating system's Add/Remove Programs list (accessible via Add/Remove Programs in the system's control panel).

The BitTorrent.Com download area has many versions available. Version 6.0 is less than 1MB (whereas version 5.2 was 6.0M according to the website's file listing). There are multiple 6.0 files, some of which have "Bundle" (or "bundle") in their name and are identical to each other: The other is 3,258 bytes larger. The resulting installed files are the same file sizes but are not identical. These were released on December 13, 2007. A web page found shows that the October 24, 2007 builds shows the non-bundle version was smaller at that time, and apparently didn't include the "DNA" code.

Blizzard Downloader
Used to update World of WarCraft, the varying versions of this come with an embedded .torrent file. At least an early version of this was based on BitTorrent. For further details, see the WoW page.
This relates to the secure FTP, and not RFC 913's Simple File Transfer Protocol.
See SSHDOS (Terminal software) for SFTP and SCP software.
32-bit Windows
PSFTP's latest version. There is also an installer that includes this from the PuTTY download page (available locally from the PuTTY download area as described by the Communications Terminal Software page). Command line application.
For a GUI application, see the SCP program WinSCP which also supports SFTP.
FTP client for Win9x/ME/NT4/2K/XP. Supports SFTP.

SCP came before SFTP. Further development plans for the protocol are not expected since SFTP has support for more features.

See SSHDOS (Terminal software) for SFTP and SCP software.
32-bit Windows
PSCP is included in an installer
PSCP's latest version is included in an installer just like PSFTP. Also like PSFTP, its home page is that of PuTTY's. There is also an installer that includes this from the PuTTY download page (available locally from the PuTTY download area as described by the Communications Terminal Software page). Command line application.

Originally an application for SCP, this now supports SFTP (as of version 3.0) and FTP (as of version 4.0) as well. This program uses a GUI and so may be preferred by some users who prefer those things. For SCP, it requires some specific things from the server that command line SCP clients don't (and by using those things on the server that it expects to be able to, WinSCP can do things other SCP clients cannot).

Using /NOCANDY may prevent WinSCP from using OpenCandy.

  • WinSCP SF.Net site
  • WinSCP.Net site has some pages with information like FAQs, and the site uses the SourceForge page for its download links.
FTP is a protocol based on telnet, and has a few small but compelling reasons why other protocols are often used instead:
  • It is based on telnet, and like telnet, offers no encryption. People capable of snooping on the connection can automatically scan for username and password prmopts. FTP's basic authentication is unsuitable for many networks, especially if they are rather public, and definitely including the Internet. FTP run over SSL does exist, but that's not supported by nearly as much software as http over SSL (https) or SFTP over SSH.
  • FTP was designed to use two connections: One for the commands (which is initiated from the client to the server), and one which has data sent (which was originally a connection initiated from the server to the client). This proves to be extremely problematic with certain newer network configurations involving firewalls and/or NAT (network address translation). The issue of dealing with a wide variety of possible port numbers can be a burden handled by the server instead of the FTP client, if the newer PASV mode is used by the both the client and the server. (This doesn't always work well for those wishing to set up servers.) In some cases, like a NAT firewall in the middle, the problems may be effectively dealt with using customized software (like an FTP proxy) at the source of the routing/translation. In such cases, this requires maintenance to set up the configuration, compared to SFTP which doesn't require any such thing.
  • http offers less overhead, and so is often used, especialy for files meant to be publicly accessible.
Web browsers
Perhaps since early web browsers supported some manner of calling FTP, and so many web pages were created that referred to FTP sites, many products supporting http (used for web pages) also support FTP (at least for downloading). This includes most/all popular web browsers. Software designed for http downloading, like wget (which does support ftp), often supports ftp (at least for downloading).
Multi-protocol software
Software that support other file transfer protocols like SFTP and SCP may also support FTP. Such software may be preferred due to its flexibility to also handle other protocols when they are needed/desired.
FTP-only software
FTP Cleints
A program called "ftp"
This is a piece of software included with many operating systems, including many Unix-like operating systems and Windows 32-bit Windows. Often this software defaults to using ASCII transfers (which frequently can be overridden by using a command called "binary"), does not support automatic recursing into subdirectories, and may or may not even support transfering multiple files using wildcards. (If it does, running the FTP command "prompt off" can be nice. For more useful commands like lcd, try issuing the help or ? commands from within the ftp program.)
NcFTP client
This program, which says it is by Mike Gleason, has supported mget (to transfer multiple files by specifying a wildcard) and defaulting to binary images for a long time, making it preferable over many (especially older) FTP clients just called "ftp". Due to its popularity on Unix-like systems, this may be a good alternative to search for (to see if it is already installed) before searching for other options. The client software is free and source code is available (unlike the NcFTPd server). NcFTP 3.2.1 for Microsoft Windows (probably requiring 32-bit Windows)
WS_FTP Limited Edition

WS_FTP Limited Edition is free for certain uses, including non-commercial. There were 16-bit releases that worked on Windows 3.x. (Windows 3.x did not have an abunance of free FTP client software available to run.) WS_FTP Limited Edition has been discontinued: Newer software from Ipswitch has 30-day evaluation periods instead of being free (indefinitely) for certain uses.

Note that using this file is likely to create a log file called WS_FTP.LOG into each local directory that files are downloaded to. (This means that downloading subdirectories recursively will create multiple such files.)

The 16-bit version of the software should work fine (but perhaps without support for long filenames?) in 32-bit Windows.

The installation program may ask how one intends to use the software, and may or may not allow installation based on the answers. (Students and staff/faculty members of an educational institution may use the software at work; others may not be allowed to do so.)

Version 5.06 was released for both 16- and 32-bit versions of Windows.

Version 5.08

The newest version of the 16-bit WS_FTP LE was 5.06: There is no 5.08 for Windows 3.x. Versions 5.07 and 5.08 were only for 32-bit Windows. The whatsnew.txt said version 5.07 had "IBM MVS changes" and version 5.08 had "AS/400 changes".

The installer calls itself "WS_FTP Limited Edition Install (32)". WS_FTP95 Limited Edition (for Windows 95, 98 and NT) Version 5.08 2000.02.23


This comes with WS_FTP95.EXE (and remove.exe). File Watcher for ws_ftple.exe (707,072 byte file) (with 80 locations) found: location 1, location 2, and more.

The following files were found with different filenames, but identical byte-for-byte to the above files: ws_ftple-5.08.exe, ws_ftple_508.exe, ws_ftple_508_en.exe, ws_ftple508.exe, ws_ftple508.exe. To have a valid short filename that is not ambiguous about the version number, the local copy is called wsfle508.exe.

Was there a non-standalone version that contained an older version? It was looking this way, but perhaps directories were being mixed together.

(Same filesize, different content: ftp://ftp.aset.psu.edu/pub/access/cd/windows/utils/ftp/ws_ftp/ws_ftpLE.exe )

Version 5.06
32-bit release
The following might be a 32-bit/16-bit combo release. Installing under Win98 resulted in an executable that said it was for Windows 95, 98, and NT:
16-bit release
The following might be a 32-bit/16-bit combo release. Installing under Win98 resulted in an executable that said it was for Windows 3.x (despite the text file saying it was for some sort of 32-bit Windows). WS_FTP LE and WS_FTP Pro Versions
Version 5.06 99.07.21 for Windows 3.x/95/98/NT 3.51/4.0 File Watcher page for 974,938 version of ws_ftp16.exe contained links to: ws_ftp16.exe (Download location #1), ws_ftp16.exe (Location #2), ws_ftp16.exe (Location #3), ws_wftp16.exe (Location #4), ws_ftp.exe (Location #5), ws_ftp16.exe (Location #6), ws_ftp16.exe (Location #7), ws_ftp16.exe (Location #8), ws_ftp16.exe (Location #9), ws_ftp16.exe (location #10), ws_ftp16.exe (Location #11), ws_ftp16.exe (Location #12)
Quite a few sites had this specific version for some reason.
(Are there any official installation package(s) that would offer both 16-bit and 32-bit verisons?)
1st Transfer
Recommended by Evrsoft, the makers of WWW browser/editor called 1st Page.
AceHTML's complementary product.
FTP servers
(This section may be expanded later)
Included with some operating systems
OpenBSD FTP server
available for other operating systems?
vsftpd / vs_ftpd
very secure?
This is the third of attractive options if seeking FTP server software that has a focus on security, and has easy licensing. Switched from GPL to BSD licensing on June 9, 2003 (per pro-pureftpd forum post).
Open source
WS_FTP, WinSCP, Wget others. FTP over SSL
HTTP uploading is supported by many WWW browsers. In addition to web browsers that often obtain just one file at a time, there are some programs that can recursively download multiple files. However, many sites do not like a lot of downloading of major portions of their site, and attempt to block these clients (at least for those people who are too ignorant or lazy or apparently incapable of changing what the program identifies itself as, which most such programs can do.)
[#curl]: cURL
  • ][CyberPillar][: Web transfering programs: cURL section
  • curl files
  • curlz753.7z is a 7z file that contains Michael Kostylev's release of 7.53.0 for DOS, as distributed by a hyperlink provided on the main cURL download page)
  • curl75w3.zip is a 7z file that contains Viktor Szakáts's release of 7.54.1 for 32-bit Microsoft Windows, as distributed by a hyperlink provided on the main cURL download page
    • curlu375.zip contains a modified version of the curl.exe from curl75w3.zip ; it was modified using UPX 3.9.4 upx.exe --best --ultra-brute -v -f -k curl.exe
  • curl75w6.zip is a 7z file that contains Viktor Szakáts's release of 7.54.1 for 64-bit Microsoft Windows, as distributed by a hyperlink provided on the main cURL download page
  • curlca75.zip was a ZIP file created containing just the curl-ca-bundle.crt found the bin subdirectory from both curl75w?.zip files listed above
[#dwnl]: dwnl
A very small HTTP(S) downloader, for ReactOS (and Microsoft Windows) - dwnl files
[#wget]: Wget

Wget is a command-line program that can download from http and ftp, and can download recursively.

If trying to use WGet for Windows, the old version WGET for Windows (wget may be one of the best bets. This file is using a fairly old version of WGet. On the plus side, some testing on a Windows XP showed this worked better than some others versions. In order to get the software to work properly, this version does not require separate downloading of Microsoft Common Runtime Library (MSCRT) Dynamic Link Library (DLL) files. This version might also work well with older 32-bit versions of Microsoft Windows. It is also one of the smaller distributions. (Also, in a Google search for wget, this version has been known to show up above/before the Wget for Windows (page on SF).)

This website has a locally made Zip of the binary and source (which, when combined, eliminates some of the size advantage available by downloading just the binary executables from the original public distribution of this version) and is stored in at the relative URL http/wget/wg1531wb.zip.

This website has also made an http/wget/wg1531wu.zip which contains a compressed version of the executable file that is found in wg1531wb.zip. The compression was done with UPX (--best --ultra-brute). The executable file is 68,096 bytes, and has been (minimally) tested in 64-bit Windows 10.

Downloading Wget links to:

In addition to the above official sources, here is an unofficial sources: The original web site's URL's April 28, 2006 version called the software Wget: The same URL's July 9, 2006 version called it "GNU Wget".
Offline Express?
WebMirror 1.40c (30-day shareware)
TOCOWS uses the exact same file, http://tucows.mundofree.com/files/wmwin140.zip , for its mirror of this for various versions of Windows (Win95/98, WinMe, WinNT, and Win2K). The software is from Marco Maccaferri (MeccaSoft) (old URL, now redirects)
Teleport Pro
Firefox add-on
Recommended by Review 46 (#34)
Trivial FTP (TFTP)

A TFTP client may come with some versions of Microsoft Windows. Be sure to use the -i switch for files that padding shouldn't be used on. Additionally, clients for this simple protocol are supported by some computer BIOSes (to download an image and boot it) and hardware devices (such as switches and routers made by Cisco).

A class from a Cisco-sponsored curriculum used http://www.solarwinds.com/products/freetools/free_tftp_server.aspx although http://tftpd32.jounin.net the main page of http://pagesperso-orange.fr/philippe.jounin/tftpd32.html says "Tftpd recommended by Cisco." After it is installed, the Help,About page identifies itself as free and gives a license prohibiting charging for distributing/copying. http://sourceforge.net/projects/tftp-server/ is GPL'ed.

The "Sorcerer's Apprentice Syndrome" protocol flaw is pointed out and hyperlinked to from Wikipedia's TFTP page.

Other protocols
The main web page refers to this as both rsync and Rsync. This remote synchronization software is designed to be run on both ends of a network connection, and is highly customizable. The “rsync download” page (rsync web site's page for downloading) has some options. The page also says it “cannot vouch for 3rd parties”. The following references for Windows downloads are not fully tested by this site's staff but are mentioned for convenience: Rsync's web page references cwrsync (Cygwin rsync). There is also DeltaCopy - Rsync for Windows.
[#ncflxfer]: netcat

Netcat is a very useful program which can perform a wide variety of tasks. It is bundled with some operating system distributions and the executable file is normally called “nc”. One of the ways that this very flexible program can be used is to create a file transfer. Note that, due to its simplicity, this doesn't cover any sort of error handling (unlike most other file transfer protocols, especially ones that are used as widely).

Examples in Unix

In these examples, the word “tcp_port” is meant to be replaced by a port number. The remote_system_ip refers to the IP address of the system being connected to. These haven't been fully tested. The examples with “| pv -b ” reference a way to show a progress bar, but that requires a separate program and isn't necessary (and it involves dual piping which may/will not work in some operating systems) so feel free to leave that off if desired.

Listening on port, sending a file
cat filename.ext | pv -b | nc -l tcp_port
Initiating connection, receiving file
nc remote_system_ip tcp_port | pv -b > filename.ext

Ncat is a separate program from the Netcat program's binary file nc. It may be fairly similar, though.

TightVNC 1.29 did not have file transfering, but the earliest development version of 1.3 does. (This program is listed in the screen-based remote access page.)
Remote file systems
Including NFS and AFS
Code repository software
CVS, others
SyncBack Freeware
SyncBack Freeware downloads page, for Win98/NT4+, recommended by 46 utils review.
[#ipxfilxf]: IPX-based File Transfering solutions
IPXFER (SendNet.Exe/RecNet.Exe)
IPXXFER v2.0 by Ron Dunlevy
With an additional X in the name compared to IPXFER which was more well known, this is freeware and supports subdirectories.
IPXCpy version 2.4, freeware by Oliver Kraus. IPXCpy 2.4 features included subdirectories and CRC checking.
IPXTrans vr. 1.0 contains IPXTRANS.DOC which is identical, byte-for-byte, to the IPXTrans vr. 1.0 documentation/text file in the idgames IPX directory.
Ken Silverman's DCopy.exe
Requiring “DOS32”, this is available from Ken Silverman's Utilities page (section on DCOPY.EXE)
[#modmxfer]: Modem-based file transfering solutions

These are solutions that were prominently used when communicating over phone lines with modems were more commonplace than IP-based solutions. Some, like Z-Modem, may have been adapted to work over IP somehow (particularly over a telnet session). For more details about serial connections or telnet connections, see the terminal programs area.

Many terminal programs have bundled support for multiple file transfer protocols, especially ZModem, XModem, and YModem. Those programs may be more convenient, supporting more features (such as testing a communication connection before transfering a file) and simply being more available in cases where a stand-alone protocol isn't installed or noticably available to download for some platform.

[#hslink]: HS/Link

HS/Link was the first popular bi-directional protocol, which allowed a user to upload a file at the same time the user was downloading a file. This may seem commonplace since the IP protocol allows completely separate streams for a wide variety of applications, but prior to HS/Link the common method of trading files was to send a file in one direction, and then to send another file in the other direction. Taking advantage of a connection's ability to communicate in both directions was able to cut connection times to nearly half of what they were. BBS software, including "WildCat!", was updated to search for uploaded files whenever downloads occurred (and to ask for descriptions if the downloader didn't give a description before starting the file transfer).

When the software is registered, it can initiate a chat session with other copies of HS/Link.

Samuel H. Smith's site (and a mirror that doesn't mention Unzip) now gives registration codes for HS/Link (for DOS type "hslink register 999 x8ib2p" and for the Windows DL version use Registration number: 999 and Activation code: a00xi8b2p ) and links to HS/Link page. (The ftp site linked to from the mirror, ftp://ftp.primenet.com/users/s/shsmith/hslink, does not work.) and FTP site. Available elsewhere: Version 1.1 documentation. The reason this project was discontinued is sad: The author's "offices were burglarized and my main software development system stolen, complete with latest backup tapes." However, he has shared what he could recover, including some source code for the DOS version.

HS/Link 1.21 Release has been made available. The following files have been found, although their original status has not been verified:

Smaller HS/Link 1.21
This file was found from two sources: HS/Link 1.21, HS/Link 1.21.
Larger HS121.ZIP
Found at Larger HS121.ZIP (from Google results #1 and Google Results #2): BLTS.ZIP is larger (but contains the same files), FILE_ID.DIZ is different, and DESC.SDI exists. Named HS121DES.ZIP locally (due to having longer descriptions).
Other files
Obtainable files
from Vector, from ozzmosis, from terminate.com
File lists
If one is really desparate to find another version, perhaps the maintainers of the following sites could be contacted: File list that points to downed FTP site URLs, txt file list references: "HS121.ZIP 139498 05/24/93 HS/Link External Protocol RELEASE v1.21 As of 4:07 pm, Thursday, May 6, 1993", "Uploaded by: Ed Boress". (This file says this site had other material uploaded by Samuel Smith.)

There has bene a claim made that it would port.

It would seem that source code is now allowed to be distributed, based on the following text: Protocol download page says:

HS/Link External Protocol 1.21B7 FULL SOURCE
My offices were burglarized and my main
software development system stolen, complete
with latest backup tapes. I am posting what
source code I could dig up, in the hopes that
others may eventually benefit from my past
work, and to keep the protocol alive, at
least in some changed form.
Samuel H. Smith shsmith@primenet.com

Similar text was on Samuel H. Smith's website, linked above and stored as a gzip locally.

Auto-download signature

HS/Link's first auto-download signature was a Ctrl-B followed by a capital R. (Written in standard C-style hexadecimal notation, that is 0x0252.) HS/Link 1.1 uses a longer signature: HS* followed by ^B and then capital R. Written in standard C-style hexadecimal notation, 0x48532A0252. (I think. HS/Link 1.1 documentation page 31 seems to indicate that is the signature.)


Sometimes called Z-Modem, this name hasn't been used by Chuck Forsberg, the creator of the protocol. ZModem supports file resuming (called Crash Recovery by Chuck Forsberg, a term trademarked by Omen Technologies, or Intelligent Crash Recovery, a term similarly trademarked which verifies the existing part's integrity before resuming), automatic downloading (where a communications program executes a ZModem download automatically when a sending ZModem's signature is detected), filename sending, compression (called ZModem-90 by Omen Technologies), quoting to avoid control characters (an improved version of which Omen Technologies calls MobyTurbo), filename sending, batch (multi-file) transfers and the ability to abort/skip a file in the batch (and having the file transfer batch simply proceed to the next file), and in-protocol chat. Some of these features, especially chat and file skipping and compression, are extentions which are not universally supported by all ZModem implementations, or even supported in the same way.

When Z-Modem software tried to send a file, it started by sending ^X followed by B00. Software would often look for this string, and respond by starting to receive a file with Z-Modem. This made Z-Modem file transferring a bit more convenient than other options which may require that the user initiate the download (and especially compared to a protocol which may require the receiver to specify the filename).

ZModem is often supported by a protocol built into a terminal program (as noted in the Modem-based file transfer solutions page). The modem-based file transfer solutions may list some stand-alone packages, and ZModem support is built into sopme of the software mentioned in the terminal software section.
Texas Zmodem (often abbreviated as “TXZM”)
Communications & Internet site by Mike Dumdei in 1993. Texas Zmodem 2.41, Texas ZModem 2.41, Texas ZModem 2.41 (from Simtel archive) is free for non-commercial use (on three systems or less), and can be used as a communications program.
PD-Zmodem v1.26 has Z-Modem code taken from an old version of Chuck Forsberg's rzsz package (earlier version from April 1988). It supports chat. Positive review says source hasn't been released.

Scott M. Baker's page says this was referred to as SuperZModem and ScottZModem. The About SB-Software page referred to it as "Scott's ZModem or Super Zmodem". Both sites have mentioned the program without offering the program for download.

This came with SIMDOS, a command prompt capable of running some internal commands (like DIR, COPY, etc.), chat functionality (when connected to other SZModem programs), a byte viewer (watching the bytes as they come in), and newer versions included SZTetris internally.

Note: In at least one version of SZModem, the internal SIMDOS command DELNUL appropriately deletes all files that are zero bytes, but as well it deletes other files. One should test this command before running "DELNUL *.*" in a main download directory. (TOOGAM, unfotunately, didn't do that once.) TOOGAM has also heard that there are rumors of this program containing a back door to allow remote access to one's machine. (This may be entirely untrue.)

SZModem 2.00
Simtel's szmod200.zip

The most common szmod200.zip file TOOGAM found was the version available from Simtel. most common form of szmod200.zip was the file from Simtel: Simtel's package is an szmod200.zip that contains a different szmod200.zip as well as other files, including an szsup200.zip with *.zip files and an SZSUP.DOC that refers to those files as *.ARJ files. This file has been renamed locally as szmodsim.zip (so that one isn't prompted to overwrite a file when extracting this file to the directory where the archvie is).

A Google search for szmod200.zip turned up more results than szmodem2.zip. However, no two copies on the Internet were the same as each other. As Scott M. Baker's websites (smbaker.com and sb-software.com) don't offer any official versions of the file, there is no compelling reason for this site to suggest one version as being more original or authentic than any of the others.

As for the SZModem2.Zip, there were two files that seemed the same, even with multiple copies.

More common SZModem2.Zip
Larger SZModem2.Zip
Another, larger SZMODEM2.ZIP, is a larger zip with a shorter FILE.ID.DIZ file Larger SZMODEM2.ZIP is identical. I decided to rename this to szmodm20.zip locally so it does not conflict with the other szmodem.zip.
SZModem ver 2.00 documentation
Supplemental Utilities 2
Sup 2 Note that this did not have all of the files from the 1.6 package: One could use what came with the 1.6 supplements (specifically the trivia was usable) in SZModem 2.00.
Supplemental Utilities 1.6
Supp 1.60, Supp 1.60.
Other addons/versions/files
Unofficial SZModem support for Logitech mouse driver
SZModem 1.6
1.6 1.6

1.5 was released. The following are simply some files that were found when looking for newer versions: 144, 141, notes referencing 1.41

GIFLink v1.12 supported multiple protocols: X/Y/ZModem and CIS QuickB, and supported direct modems, FOSSIL, or INT 14H. It allowed GIF graphics to be viewed while they were downloading, and supported the often-unsupported Skip option of Z-Modem so one could abort one graphic in a batch of downloads if the graphic was considered undesirable while it was being downloaded. (Bandwidth speeds were slower, so aborting the download of even a single graphic file might have noticeably saved time.) Since web browsers like Netscape hadn't been released (or, at least, very widely known) yet, this could be a time saver compared to the other option of downloading the entire GIF and then viewing it after the download is complete. This share is made by the authors of Telemate and GIFLITE. Released versions include 1.00, 1.12, 1.20, and it seems 2.01.

The following might not be official archives.

giflk120.zip matched the results of FTP searches: 1.20 1.20 (which came from ftp search 1 and FTP search 2).
GIFLink v1.12 (does not have giflink.gif file) v1.12 (comment says tested by The Pier) v1.12 (zip w/ Channel 1 ad) 1.12 w/ another BBS ad copy of last link.
GIFLink v1.11
GIFLink 1.0
[#freebycf]: Chuck Forsberg's free material
Public domain version of rzsz (source code)
A version from April 1988 of which was public domain code that some other authors used for other Zmodem code. A page says files were available from ftp://oak.oakland.edu/pub/misc/unix/rzsz-pd.zip. Goodies points to rzsz-pd.zip: April 1988 Public Domain Zmodem source code. TOOGAM also found copy 2 of rzsz-pd.zip: April 1988 Public Domain Zmodem source code.
XModem, YModem, and ZModem documentation
YZModem documentation package. A text version of the Zmodem documentation, without the backspace characters is also available.
Shareware from Chuck Forsberg's Omen Technologies

These versions were shareware. Many programs referred to these as reference. If one could get these set up, other protocols could generally be set up in much the same way. There may have been some claim of these going faster (perhaps with HST modems at least), but other software could generally maximize a modem's capability just fine. GSZ was the graphical version of DSZ. As they are shareware and offer no real benefits over other options, this site doesn't actually carry distributions of the unneeded software.

Apparently this is the successor to Chuck Forsberg's rzsz package, described elsewhere. The README file in the rzsz-pd package says that the "shareware program".... "DSZ provides a "mini term function" that supports ZMODEM AutoDownload."

rzsz Shareware version

Note that there is an older version in the public domain, listed in the free section.

Chuck Forsberg's rzsz package has multiple versions available. The more recent (rzsz.zip shareware source is an update to the public domain code. Its license agreement forbids transfering files with Zmodem programs that are based on the public domain code.

XModem, YModem

YModem is an older protocol than ZModem. YModem-G may be a bit faster than ZModem. Otherwise, there is no particular advantage of YModem over ZModem. XModem is older than YModem and has no noteworthy advantages over YModem. These protocols are mentioned here due to their widespread support: Support for these protocols is built into many pieces of communications terminal software, and other software (such as GIFLink) which support ZModem.

There are multiple variants of Ward Christensen's XModem and YModem protocols, as documented in YModem.Doc which is a part of the YZModem.Zip file located in the ZModem section. (These are older protocols supporting less features than ZModem.) The basic XModem protocol is sometimes called XModem-Csum (referring to its usage of a checksum for verifying data sent).

YModem sends filenames and supports batch transfers. Be warned that at least some XModem implementations pad files (potentially making the resulting file that the destination ends up with larger than the original file on the sending computer).

{Commo}'s documentation indicates that {Commo} supports XModem-G (streaming XModem). (This is mentioned because such support is not common, or at least not commonly documented.)

Apparently supported somehow for Northern Lights BBS. (This might only be working with Telnet connections rather than modem connections, but is listed here since it seems to be supported by BBS software.)
Information is available from Communications & Internet page.
Compuserve Information Service (CIS) Quick-B, B, B+
http://www.filegate.net/comm/ looks to have this. {Commo} comes bundled with a file called BPLUS.POV which is executed directly (with {Commo}'s exec-d internal command) and which starts with MZ like a normal DOS executable does.
This is supported by the XC terminal program. XC .tar.gz, XC LSM
Ken Silverman's Utilites Page (section for CCopy.exe) describes this program as being able to copy “files at 115,200 baud using the serial port” and supporting a resume ability.
Serial port/cable, parallel port/cable solutions (direct connections)
Serial ports could have external programs connected: Therefore the modem-based solutions listed elsewhere on this site also work for serial ports with the right hardware.
InterSvr, InterLnk
The InterSvr server and the related InterLnk client came with MS-DOS 6, and are available as part of the MS-DOS Utilities package (OLDDOS.EXE) for Win95.