tony.chamberlain@xxxxxxxxx wrote:
> I am curious how the pppd pty process (in this case ppp_relay) communicates
> to pppd? We did a netstat and found pppd but no TCP nor UDP ports were
> associated with it. It was just a UNIX-type process.
The ppp_relay process will have stdin and stdout connected to the master
side of a pty pair. Pppd then configures PPP to run on the slave side.
Pppd is completely unaware of what that child process is doing; it
won't have any network ports open.
The process run by the pppd "pty" option should read and write
AHDLC-encoded PPP packets on standard input and output. Where and how
it gets those packets are a problem for the person writing ppp_relay.
Or, as the fine man page says:
pty script
Specifies that the command script is to be used to communicate
rather than a specific terminal device. Pppd will allocate
itself a pseudo-tty master/slave pair and use the slave as its
terminal device. The script will be run in a child process with
the pseudo-tty master as its standard input and output. An
explicit device name may not be given if this option is used.
(Note: if the record option is used in conjuction with the pty
option, the child process will have pipes on its standard input
and output.)
--
James Carlson 42.703N 71.076W <carlsonj@xxxxxxxxxxxxxxx>
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