OpenBSD Journal

A Tool for Serial Port Sharing: comms/sredird

Contributed by mbalmer on from the my-com-is-your-com dept.

Alexey E. Suslikov made a port of sredird, which has recently been added to our ports tree:

Sredird is a serial port redirector that is compliant with the RFC 2217 "Telnet Com Port Control Option" protocol. This protocol lets you share a serial port through the network.

See http://freshmeat.net/projects/sredird/ for more information on sredird.

(Comments are closed)

Comments

  1. By Anonymous Coward (69.70.207.240) on

    This sounds really nifty, I could have sworn I've needed something like this in the past, but I just can't recall for what?

    What types scenarios would some of you use this for, or how?

    Comments

    1. By Anonymous Coward (72.66.67.63) on

      > I've needed something like this in the past, but I just can't recall for what?

      Probably to share serial ports over a network.

      Just a hunch. ;-)

    2. By baldusi (201.235.107.247) on

      > This sounds really nifty, I could have sworn I've needed something like this in the past, but I just can't recall for what?
      >
      > What types scenarios would some of you use this for, or how?

      I don't really know how safe it is. I've got some switches connected by serial to a machine and I usually have to ssh to connect, this would save a step that I've already scripted for...
      But may be for some serial controlled applications where you don't need the overhead of a shell account?

      Comments

      1. By Anonymous Coward (81.168.66.243) on

        > I don't really know how safe it is.

        Safe like telnet! Run it on a secured network, to a box running something like conserver which you SSH to. Same as most other low-ish cost boxes people use as terminal servers (cisco 25xx, annex, [...]).<p>

        Windows users reading this might be interested to know how to <a href="http://www.hw-group.com/products/hw_vsp/index_en.html">use RFC2217 as a virtual com port</a>: this used to be used for networked modem banks, etc.

    3. By Ted (65.78.76.129) on

      socat or the Perly IO::All are also options...

      > This sounds really nifty, I could have sworn I've needed something like this in the past, but I just can't recall for what?
      >
      > What types scenarios would some of you use this for, or how?

    4. By Anonymous Coward (216.220.116.154) on

      > What types scenarios would some of you use this for, or how?

      Let's say you've got an OBSD server in the closet, and there's a modem hanging off of it. You've got DSL or cable, so the modem is basically unused. But for one reason or another, you need to dial out from another machine (perhaps a windows box) to send a fax, test a dialup number, etc.

      Instead of dragging the modem out, crawling under your desk to connect it, dragging a phone line over, etc. you just use the "networked" modem instead.

      ps - love the figlet "captcha"

    5. By Alexey E. Suslikov (195.68.219.2) on

      > This sounds really nifty, I could have sworn I've needed something like this in the past, but I just can't recall for what? > > What types scenarios would some of you use this for, or how?

      there are number of old DOS/WIN16 user applications which (hopefully) run under newer Windows' but use modems directly.

      this is very annoying, to have analogue modems directly attached to workstations, so I decided to use networked port with full RS-232 signalling emulation (RFC 2217).

      client-side software can be the Cisco Dialout Utility. Dialout/EZ is also the option. server-side is the sredird.

      now I have only one(!) analogue modem connected to OpenBSD box in my server room to handle dialout from 5 to 10 workstations. however, there is one connection from one client at time, but this is an adequate pay for huge simplification of my network.

      additionally, Cisco routers have "rotary" option, when all RS-232 ports visible under single TCP-port number and router establishes connection with client-side using first free port. sredird lacks this knob, but one always can redirect each modem to dedicated TCP-port.

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