From: allredkl@choc01.dnet.dupont.com (Kevin L. Allred, 615-875-7167)
Subject: RE: Linux-Activists Digest #86
Reply-To: allredkl@choc01.dnet.dupont.com (Kevin L. Allred, 615-875-7167)
Organization: The Internet
Date: Thu, 3 Sep 1992 17:18:36 GMT

"nealstep@nexus.yorku.ca (Neal Stephenson)" writes:
| Subject: TCP/IP works (yippee) but still some problems : -(

|        I installed the tcp/ip package and it compiled without errors.
| I then increased the number of pty's to 64 and mknod'ed all of them,
| under the assumption that each telnet in used up one (is this right?).
| I then rebooted.
|         I can now ftp out of the system perfectly, it works great and
| since that was the main use, I am very happy (congrats to all
| concerned). :-) :-) :-)
|         However, if I ftp in I hang. Also telnetting out connects to
| the host and then locks up the keys at the password prompt. you can
| however send a ctrl-d to end the login attempt (if it's a unix box) or
| a ctrl-z for a vax, strange.
|        for telnetting in the same kind of problems are encountered.
| if you telnet in to an account that has no passwd (horrible securety,
| i know) it works fine. but if you try one that has a password it locks
| up on the password prompt.
|        last few points. perhaps they are relevant. telneting out is
| very stacatto get packets then nothing then packet. and after telneting
| in when you log out it does not remove the name from the active users
| list.
|        If all of these questions have allready been answered, if
| you could let me know where I can find the answers I'd appreciate it.

| Hardware and software:
|        486/50 16M ram 425M scsi drive 64M & 50M linux minix style
|                partitions and an 8M swap partition.
|        Cardianl ET4000 video card with 1M and Nec 5fg monitor
|        ethernet is a WD8013 on irq 10 I/O 300 mem starting at cc000
|                16K RAM.

I have had very similar experiences (with a very similar setup).  The
system I need to communicate with lies on the other side of a router
and a 56Kbps link.  When I ping my linux system from the remote
computer I see round trip times of (min/ave/max 109/173/746 ms) with a
1% packet loss.  I exchanged mail with Ross Biro about the problem,
and he told me that current linux TCP/IP code doesn't slow down the
rate at which it send packets even when it receives a signal from the
router to do so.  He says that the linux host is probably overloading
the router with packets, thus producing hung connections.  He
suggested a temporary solution that works by cripling the server so it
can't send packets too fast, but I am reluctant to try this approach.

A better approach would be to fix the server so it payes attention to
router signals to slow down.  I looked at the net source code for a
a little while, but it was clear that it is going to take deep
understanding to add this type capability.

Since at one time or another, most everyone who uses tcp/ip will want
to contact a machine at a remote sight, the slow down feature would
seem to be necessary for robust communication.  Are there any network
skilled volunteers willing to try adding this feature?

	Thanks,
	Kevin L. Allred
	allredkl@choc01.dnet.dupont.com