VMODEM

Msg # 493 of 493 on Fidonet OS/2 Disussions
To: TOMMI KOIVULA, From: TORSTEN BAMBERG
Time: Friday, 8-23-19, 9:19
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Hallo Tommi!

21.08.2019 20:01, Tommi Koivula schrieb an Torsten Bamberg:

>> Currently my vmodem and telnet ports are down, but usually I have 8
>> telnet ports running, with one instance of vmodem(2k).
 TK> 8 different TCP ports?
I meant telnet-sessions simultanously. Of course only port 23 is attached.

 TK> My Vmodem of SIO 1.60 has 16 "ports", but listening only one TCP port.
I'm using sio2k. sio2k supports 256 'sessions', witch can be telnet, com-
ports or com emulated capi-devices. I've got one big problem with sio2k, I
can't register it any more.

 TK> Which is 23 BTW. And that port is not exposed to the internet, my
 TK> router forwards external port 32 to port 23 at OS/2 computer.
Ahm, i've got a special security configuration, not only because of the
'unclosed session bug' from sio2k


  cable -->-- cable-router -->-- Router 1         Firewall 1
    dsl -->--  dsl-modem   -->-- BSD-Router -->-- BSDFirewall
                                                   |   |   |--->--- DMZ
                                                   |   |
                                                   |   |--->--- LAN
                                                   |
                                               -> Firewall 2
                                               |  with fail2ban BSD
                                                   |
                             RexxLogScripting  ^   |
                                               |  Telnet on
                                               -- Mailbox 01

Security by obscurity. ;-)

>> But there is one big bug with vmodem; if the clientsession isn't
>> closed properly, vmodem hangs up the whole computer without a trap.
 TK> Oh?
Jap. If more than 256 connections are opend, and not properly closed, sio2k
does hang up the system.

 TK> 'Tommi
Bye/2 Torsten

... MAILBOX01 on OS2: up 1d 18h 29m load: 35 proc, 129 threads (tbupv1.1)
--- GoldED+ 1.1.5-19
 * Origin: DatenBahn BBS Hamburg (2:240/5832)

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