Re: Telnet Server

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

M
Hello Shannon,

I tested the information I sent earlier on VRM440 and found that it no longer
works.  As part of the architectural change to Telnet that occured at 440 the
QTGSTART program (which is what gets called by STRTCPSVR *TELNET) gets to see
if TELNET is currently active.  It is not doing that by checking the port
however I haven't bothered trying to find out what it does check.  QTGSTART
sends TCP1A04 - "Telnet currently active" if it finds Telnet is already
running.

The nett result is that on 440 and later releases only one instance of TELNET
can be active.  That single instance can (and does) listen on multiple ports
but they haven't written it to handle more than one port per service name.
They probably just use getservbyname() which returns the first entry with the
requested name and protocol from the SERVICES table.  That approach is
reasonable and consistent with most TCP applications.  You could raise a DCR
and request they use getservent() and then they could process all the entries
in the SERVICES table.  I notice that TELNET uses accept() rather than the more
useful select() so they would have a bit of work to implement multiple servers.

Regards,
Simon Coulter.

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