Thanks very much, Clifford.
I compiled and ran "tcflush.c". It seems to do the trick (even without
eliminating the 'ABORT "NO CARRIER"' line in my chat script). I have
decided to include a "tcflush < /dev/modem" in my dialup script.
Wes
Clifford Kite wrote:
>
> On Tue, 16 Feb 1999, Wes Morriston wrote:
>
> |Right after I posted the output in /var/log/messages to the list, I
> |decided to try the chat script without the 'ABORT "NO CARRIER"' line.
> |The problem disappeared completely.
> |
> |Here's what I think. The "NO CARRIER" returned by the modem after a
> |previous disconnect stays in the pipeline and gets recovered by the chat
> |script the next time a try to reconnect. That squares with something I
> |just remembered - viz., that the first time in the morning that I try to
> |connect I don't have this problem. I think the problem appears only
> |after a previous disconnect.
>
> Good! I think you are right. This is what I suspected I but wanted to
> see an actual log before mentioning it. More below.
>
> |Two questions. (1) Is there any real reason not to eliminate the 'ABORT
> |"NO CARRIER"' line from my chat script? (2) What is the best way to
> |flush the buffer completely when I disconnect?
>
> No reason that the ABORT "NO CARRIER" shouldn't be omitted - except then it
> won't abort, presumably.
>
> This was a problem for someone else and he posted the answer he came up
> with. I saved the post because the problem was so unique. He was having
> trouble with demand dialing, and this his post in it's entirety:
>
> ---Begin Post-----------------------------------------------------------
>
> >From [EMAIL PROTECTED] Tue Feb 16 20:24:11 1999
> Date: 11 May 1998 21:08:50 -0500
> From: Gregory Travis <[EMAIL PROTECTED]>
> Newsgroups: comp.os.linux.networking
> Subject: Re: ip masquerading and dial on demand (pppd 2.3.5)
>
> In article <6j89q6$9p8$[EMAIL PROTECTED]>,
> Kevin Martin <[EMAIL PROTECTED]> wrote:
> >In article <6j85eg$pr4$[EMAIL PROTECTED]>, it says [EMAIL PROTECTED] wrote:
> >>A couple of people have told me that IP Masquerade requires a
> >>static address. Anybody know whether that's still true?
> >
> >The pppd man page for 2.3.4 says that demand dialing is "not recommended"
> >if you'll be assigned a dynamic address. THAT makes it seem bloody useless
> >to me... and I had such hopes for it when I first read about it here.
>
> Here's what I did to FINALLY get demand-dialing to work under Red Hat 5.0
> (kernel 2.0.33) using dynamic addresses.
>
> My pppd line, executed at startup, is:
>
> /usr/sbin/pppd -detach lock modem crtscts defaultroute
> 192.168.1.2:192.168.1.1 /dev/modem 115200 remotename ppp0
> ipparam ppp0 demand nopersist idle 1200 ipcp-accept-remote
> ipcp-accept-local
> connect /usr/sbin/chat -f /etc/sysconfig/network-scripts/chat-pp
>
> (this is executed by RedHat's startup script - I configured all of the above
> through the control panel giving most of the demand dial options seen in
> the "additional arguments" window. I also set it to automatically
> RESTART pppd if it exits)
>
> Note several things that I found:
> 1. The "persist" option is buggy, at least in pppd 2.3.3. Hence
> the explicit "nopersist" on the command-line and the
> requirement to restart pppd if it exits.
> 2. You >should< flush the modem buffer prior to starting pppd. I
> was trying to figure out why PPP/Chat would sometimes fail
> right after starting. Turns out there was a stale "NO CARRIER"
> in the tty buffer left over from the last time the modem line
> was dropped. I wrote a little program to flush the buffer
> and stuck the program in redhat's ppp script (see below).
>
> It works really well now - we use ipfwadm at home for our other computers
> and they spark up the line just fine.
>
> ------- Begin change to redhat ppp script
> ( /etc/sysconfig/network-scripts/ifup-ppp )
>
> .
> .
> .
> while : ; do
> (logger -p daemon.info -t ifup-ppp \
> "pppd started for $DEVICE on $MODEMPORT at $LINESPEED" &)&
>
> > /var/run/ppp-$DEVICE.dev
> + /usr/local/bin/tcflush < $MODEMPORT
> /usr/sbin/pppd -detach $opts $MODEMPORT $LINESPEED \
> remotename $DEVICE ipparam $DEVICE \
> ${PPPOPTIONS} \
> connect "/usr/sbin/chat $chatdbg -f $CHATSCRIPT"
> .
> .
> .
>
> ------ End change ("+" signifies added line)
>
> ------ Begin source to tcflush.c
> ( compile as cc -O2 tcflush.c -o /usr/local/bin/tcflush )
> #include <termios.h>
> #include <unistd.h>
>
> main()
> {
> if(tcflush(0, TCIOFLUSH)) {
> perror("tcflush");
> }
>
> exit(0);
> }
> ------- End source
>
> --- End Post -----------------------------------------------------------
>
> Cheers
> ---
> Clifford Kite Not a guru. (tm)
> [EMAIL PROTECTED] Not even close.
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