__                   /  \                  /|oo \                 (_|  /_)                  _`@/_ \    _                 |     | \   \\                 | (*) |  \   ))    ______       |__U__| /  \//   / FIDO \       _//|| _\   /  (________)     (_/(_|(____/ (c) John Madil
Traditional FidoNet logo by John Madil

FidoNet is a worldwide computer network that is used for communication between bulletin board systems (BBSes). It uses a store-and-forward system to exchange private (email) and public (forum) messages between the BBSes in the network, as well as other files and protocols in some cases.

The FidoNet system was based on a number of small interacting programs. Only one of these interacted with the BBS system directly and was the only portion that had to be ported to support other BBS software. This greatly eased porting, and FidoNet was one of the few networks that was widely supported by almost all BBS software, as well as a number of non-BBS online services. This modular construction also allowed FidoNet to easily upgrade to new data compression systems, which was important in an era using modem-based communications over telephone links with high long-distance calling charges.

The rapid improvement in modem speeds during the early 1990s, combined with the rapid decrease in price of computer systems and storage, made BBSes increasingly popular. By the mid-1990s there were almost 40,000 FidoNet systems in operation, and it was possible to communicate with millions of users around the world. Only UUCPNET came close in terms of breadth or numbers; FidoNet's user base far surpassed other networks like BITNET.[citation needed]

The broad availability of low-cost Internet connections starting in the mid-1990s lessened the need for FidoNet's store-and-forward system, as any system in the world could be reached for equal cost. Direct dialing into local BBS systems rapidly declined. Although FidoNet had shrunk considerably since the late 1990s, it has remained in use even today[citation needed] despite internet connectivity becoming universally available.



Hand-compiled list of Fido BBS systems, June 1984. This document formed the basis of the first nodelists.

There are two major accounts of the development of the FidoNet, differing only in small details.

Tom Jennings' account

Around Christmas 1983, Tom Jennings started work on a new MS-DOS–hosted bulletin board system that would emerge as Fido BBS. Jennings set up the system in San Francisco some time in early 1984. Another early user was John Madil, who was trying to set up a similar system in Baltimore on his Rainbow 100. Fido started spreading to new systems, and Jennings eventually started keeping an informal list of their phone numbers, with Jennings becoming #1 and Madil #2.[1]

Jennings released the first version of the FidoNet software in June 1984. In early 1985 he wrote a document explaining the operations of the FidoNet, along with a short portion on the history of the system. In this version, FidoNet was developed as a way to exchange mail between the first two Fido BBS systems, Jennings' and Madil's, to "see if it could be done, merely for the fun of it". This was first supported in Fido V7, "sometime in June 84 or so".[2][3][4]

Ben Baker's account

In early 1984, Ben Baker was planning on starting a BBS for the newly forming computer club at the McDonnell Douglas automotive division in St. Louis. Baker was part of the CP/M special interest group within the club.[5] He intended to use the seminal, CP/M-hosted, CBBS system, and went looking for a machine to run it on. The club's president told Baker that DEC would be giving them a Rainbow 100 computer on indefinite loan, so he made plans to move the CBBS onto this machine. The Rainbow contained two processors, an Intel 8088 and a Zilog Z80, allowing it to run both MS-DOS and CP/M, with the BBS running on the latter. When the machine arrived, they learned that the Z80 side had no access to the I/O ports, so CBBS could not communicate with a modem. While searching for software that would run on the MS-DOS side of the system, Baker learned of Fido through Madil.[1]

The Fido software required changes to the serial drivers to work properly on the Rainbow. A porting effort started, involving Jennings, Madil and Baker. This caused all involved to rack up considerable long distance charges as they all called each other during development, or called into each other's BBSes to leave email. During one such call "in May or early June", Baker and Jennings discussed how great it would be if the BBS systems could call each other automatically, exchanging mail and files between them.[1] This would allow them to compose mail on their local machines, and then deliver it quickly, as opposed to calling in and typing the message in while on a long-distance telephone connection. Jennings responded by calling into Baker's system that night and uploading a new version of the software consisting of three files: FIDO_DECV6 (the new version of the BBS program itself), FIDONET, and NODELIST.BBS. The new version of FIDO BBS had a timer that caused it to exit at a specified time, normally at night, and as it exited it would run the separate FIDONET program. NODELIST was the list of Fido BBS systems, which Jennings had already been compiling.[1]

The FIDONET program was what later became known as a mailer. FIDO was modified to use a previously unused numeric field in the message headers to store a node number for the machine the message should be delivered to. When FIDONET ran, it would search through the email database for any messages with a number in this field. FIDONET collected all of the messages for a particular node number into a file known as a message packet. After all the packets were generated, one for each node, the FIDONET program would look up the destination node's phone number in NODELIST.BBS, and call the remote system. Provided that FIDONET was running on that system, the two systems would handshake and, if this succeeded, the calling system would upload its packet, download a return packet if there was one, and disconnect. FIDONET would then unpack the return packet, place the received messages into the local system's storage, and move onto the next packet. When there were no remaining packet, it would exit, and run the FIDO BBS program.[6]

In order to lower long distance charges, the mail exchanges were timed to run late at night, normally 4 AM.[2] This would later be known as national mail hour,[7] and, later still, as Zone Mail Hour.

Up and running

By June 1984 Version 7 of the system was being run in production, and nodes were rapidly being added to the network. By August there were almost 30 systems in the nodelist, 50 by September, and over 160 by January 1985. As the network grew, the maintenance of the nodelist became prohibitive, and errors were common. In these cases people would start receiving phone calls at 4 AM, from a caller that would say nothing and then hang up. In other cases the system would be listed before it was up and running, resulting in long distance calls that accomplished nothing.[2]

In August 1984 Jennings handed off control of the nodelist to the group in St. Louis, mostly Ken Kaplan and Ben Baker. Kaplan had come across Fido as part of finding a BBS solution for his company, which worked with DEC computers and had been given a Rainbow computer and a USRobotics 1200bit/s modem.[8] From then on, joining FidoNet required one to set up their system and use it to deliver a netmail message to a special system, Node 51. The message contained various required contact information. If this message was transmitted successfully, it ensured that at least some of the system was working properly. The nodelist team would then reply with another netmail message back to the system in question, containing the assigned node number. If delivery succeeded, the system was considered to be working properly, and it was added to the nodelist.[2] The first new nodelist was published on 21 September 1984.[1]

Nets and nodes

Growth continued to accelerate, and by the spring of 1985 the system was already reaching its limit of 250 nodes. In addition to the limits on growth of what was clearly a popular system, nodelist maintenance continued to grow more and more time consuming.[1]

It was also realized that Fido systems were generally clustered – of the 15 systems running by the start of June 1984, 5 of them were in St. Louis.[1] A user on Jennings's system in San Francisco that addressed emails to different systems in St. Louis would cause calls to be made to each of those BBSes in turn. Local calls were normally free or charged at a low rate. Additionally, the initial call setup, generally the first minute of the call, was normally billed at a higher rate than continuing an existing connection. Therefore, it would make sense to deliver all the messages from all the users in San Francisco to all of the users in St. Louis in a single call. Packets were generally small enough to be delivered within a minute or two, so delivering all the messages in a single call could greatly reduce costs by avoiding multiple first-minute charges. Once delivered, the packet would be broken out into separate packets for local systems, and delivered using multiple local free calls.

The team settled on the concept of adding a new network number patterned on the idea of area codes.[N 1] A complete network address would now consist of the network and node number pair, which would be written with a slash between them. All mail travelling between networks would first be sent to their local network host, someone who volunteered to pay for any long distance charges. That single site would collect up all the netmail from all of the systems in their network, then re-package it into single packets destined to each network. They would then call any required network admin sites and deliver the packet to them. That site would then process the mail as normal, although all of the messages in the packet would be guaranteed to be local calls.[1]

The network address was placed in an unused field in the Fido message database, which formerly always held a zero. Systems running existing versions of the software already ignored the fields containing the new addressing, so they would continue to work as before; when noticing a message addressed to another node they would look it up and call that system. Newer systems would recognize the network number and instead deliver that message to the network host. To ensure backward compatibility, existing systems retained their original node numbers through this period.[1]

A huge advantage of the new scheme was that node numbers were now unique only within their network, not globally. This meant the previous 250 node limit was gone, but for a variety of reasons this was initially limited to about 1,200. This change also devolved the maintenance of the nodelists down to the network hosts, who then sent updated lists back to Node 51 to be collected into the master list. The St. Louis group now had to only maintain their own local network, and do basic work to compile the global list.[1]

At a meeting held in Kaplan's living room in St. Louis on 11 April 1985[N 2] the various parties hammered out all of the details of the new concept. As part of this meeting, they also added the concept of a region, a purely administrative level that was not part of the addressing scheme. Regional hosts would handle any stragglers in the network maps, remote systems that had no local network hosts. They then divided up the US into ten regions that they felt would have roughly equal populations.[1]

By May, Jennings had early versions of the new software running. These early versions specified the routing manually through a new ROUTE.BBS file that listed network hosts for each node. For instance, an operator might want to forward all mail to St. Louis through a single node, node 10. ROUTE.BBS would then include a list of all the known systems in that area, with instructions to forward mail to each of those nodes through node 10. This process was later semi-automated by John Warren's NODELIST program.[9] Over time, this information was folded into updated versions of the nodelist format, and the ROUTES file is no longer used.[10]

A new version of FIDO and FIDONET, 10C, was released containing all of these features. On 12 June 1985 the core group brought up 10C, and most Fido systems had upgraded within a few months.[9] The process went much smoother than anyone imagined, and very few nodes had any problems.[1]


Some time during the evolution of Fido, file attachments were added to the system, allowing a file to be referenced from an email message. During the normal exchange between two instances of FIDONET, any files attached to the messages in the packets were delivered after the packet itself had been up or downloaded. It is not clear when this was added, but it was already a feature of the basic system when the 8 February 1985 version of the FidoNet standards document was released, so this was added very early in Fido's history.

At a sysop meeting in Dallas, the idea was raised that it would be nice if there was some way for the sysops to post messages that would be shared among the systems.[11] In February 1986 Jeff Rush, one of the group members, introduced a new mailer that extracted messages from public forums that the sysop selected, in a manner similar to the way the original mailer handled private messages. The new program was known as a tosser/scanner. The tosser produced a file that was similar (or identical) to the output from the normal netmail scan, however, these files were then compressed and attached to a normal netmail message as an attachment. This message was then sent to a special address on the remote system. After receiving netmail as normal, the scanner on the remote system looked for these messages, unpacked them, and put them into the same public forum on the original system.[7]

In this fashion, Rush's system implemented a store and forward public message system similar to Usenet, but based on, and hosted by, the FidoNet system. The first such echomail forum was one created by the Dallas area sysops to discuss business, known as SYSOP. Another called TECH soon followed. Several public echos soon followed, including GAYNET and CLANG. These spawned hundreds of new echos, and led to the creation of the Echomail Conference List (Echolist) by Thomas Kenny in January 1987.[12] Echomail produced world-spanning shared forums, and its traffic volume quickly surpassed the original netmail system. By the early 1990s, echo mail was carrying over 8 MB of compressed message traffic a day, many times that when uncompressed.[7]

Echomail did not necessarily use the same distribution pathways as normal netmail, and the distribution routing was stored in a separate setup file not unlike the original ROUTES.BBS. At the originating site a header line was added to the message indicating the origin system's name and address. After that, each system that the message traveled through added itself to a growing PATH header, as well as a SEENBY header. SEENBY prevented the message from looping around the network in the case of mis-configured routing information.[7]

Echomail was not the only system to use the file attachment feature of netmail to implement store-and-forward capabilities. Similar concepts were used by online games and other systems as well.

Zones and points

The evolution towards the net/node addressing scheme was also useful for reducing communications costs between continents, where timezone differences on either end of the connection might also come into play. For instance, the best time to forward mail in the US was at night, but that might not be the best time for European hosts to exchange. Efforts towards introducing a continental level to the addressing system started in 1986.[7]

At the same time, it was noted that some power users were interested in using FidoNet protocols as a way of delivering the large quantities of echomail to their local machines where it could be read offline. These users did not want their systems to appear in the nodelist - they did not (necessarily) run a bulletin board system and were not publicly accessible.[7] A mechanism allowing netmail delivery to these systems without the overhead of nodelist maintenance was desirable.

In October 1986 the last major change to the FidoNet network was released, adding zones and points. Zones represented major geographical areas roughly corresponding to continents. There were six zones in total, North America, South America, Europe, Oceania, Asia, and Africa. Points represented non-public nodes, which were created privately on a BBS system. Point mail was delivered to a selected host BBS as normal, but then re-packaged into a packet for the point to pick up on-demand. The complete addressing format was now zone:net/node.point, so a real example might be Bob [email protected]:250/250.10.[7] Points were widely used only for a short time, the introduction of offline reader systems filled this role with systems that were much easier to use. Points remain in use to this day, but are less popular than when they were introduced.

Other extensions

Although FidoNet supported file attachments from even the earliest standards, this feature tended to be rarely used and was often turned off. File attachments followed the normal mail routing through multiple systems, and could back up transfers all along the line as the files were copied. A solution was offered in the form of file requests, which made file transfers driven by the calling system and used one-time point-to-point connections instead of the traditional routing. Two such standards became common, "WaZOO" and "Bark", which saw varying support among different mailers. Both worked in a similar fashion, with the mailer calling the remote system and sending a new handshake packet to request the files.[13][14]

Although FidoNet was, by far, the best known BBS-based network, it was by no means the only one. From 1988 on, PCBoard systems were able to host similar functionality known as RelayNet, while other popular networks included RBBSNet from the Commodore 64 world, and AlterNet. Late in the evolution of the FidoNet system, there was a proposal to allow mail (but not forum messages) from these systems to switch into the FidoNet structure.[15] This was not adopted, and the rapid rise of the internet made this superfluous as these networks rapidly added internet exchange, which acted as a lingua franca.

Rapid rise, 1996 peak, and slower decline in number of Fidonodes


FidoNet started in 1984 and listed 100 nodes by the end of that year. Steady growth continued through the 1980s, but a combination of factors led to rapid growth after 1988. These included faster and less expensive modems, and rapidly declining costs of hard drives and computer systems in general. By April 1993 the FidoNet nodelist contained over 20,000 systems. At that time it was estimated that each node had, on average, about 200 active users. Of these 4 million users in total, 2 million users commonly used echomail, the shared public forums, while about 200,000 used the private netmail system.[7] At its peak, FidoNet listed approximately 39,000 systems.[2][N 3]

Throughout its lifetime, FidoNet was beset with management problems and infighting. Much of this can be traced to the fact that the inter-net delivery cost real money, and the traffic grew more rapidly than decreases caused by improving modem speeds and downward trending long distance rates. As they increased, various methods of recouping the costs were attempted, all of which caused friction in the groups. The problems were so bad that Jennings came to refer to the system as the "fight-o-net".[16]


As modems reached speeds of 28.8 kbit/s, the overhead of the TCP/IP protocols were no longer so egregious and dial-up Internet became increasingly common. By 1995 the bulletin board market was reeling as users abandoned local BBS systems in favour of larger sites and web pages, which could be accessed worldwide for the same cost as accessing a local BBS system. This also made FidoNet less expensive to implement, because inter-net transfers could be delivered over the Internet as well, at little or no marginal cost. But this seriously diluted the entire purpose of the store-and-forward model, which had been built up specifically to address a long-distance problem that no longer existed.

The FidoNet nodelist started shrinking, especially in areas with widespread availability of internet connections. This downward trend continues, but has levelled out at approximately 2,500 nodes.[N 4] FidoNet remains popular in areas where Internet access is difficult to come by, or expensive.


There is now (~2014) a retro movement which is resulting in a slow increase in internet connected BBS and nodes. Telnet, Rlogin, and SSH are being used between systems. This means you can telnet to many BBS worldwide as cheaply as ones next door. Also Usenet and internet mail has been added, along with long file names to many newer versions of BBS software, some being free-ware, resulting in increasing use. The deaf and blind are also able to access this better than the internet as a whole as interfaces for them deal mostly with ASCII text which exists in most BBS. They find it helps them communicate without the complications of pictures and audio in their internet mail and communication in general. Nodelists are no longer declining in all cases.

Other Languages
català: FidoNet
čeština: FidoNet
dansk: FidoNet
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eesti: FidoNet
Ελληνικά: Fidonet
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Esperanto: FidoReto
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polski: Fidonet
português: FidoNet
русский: Фидонет
српски / srpski: FidoNet
suomi: FidoNet
svenska: FidoNet
українська: Фідонет
中文: FidoNet