UNIX for Advanced & Expert Users

Receiving the above error from an application. I narrowed it down to a problem with rsh. If the rsh command is issued too rapidly it fails intermittently.

Try this script on your linux box...

#!/bin/sh -f
for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
do
echo $i
rsh `hostname` "echo $i" &
done

If you don't get the error right away, try running the script a few times in close succession.

I think the problem is with the /etc/xinetd.conf settings. Anyone know what flag or setting we have to tweek to avoid this problem?


Here's part of the output....
17
18
19
20
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
poll: protocol failure in circuit setup
1
17
9
16
13
6

inetd does rate-limiting. By default it stops at 40 connections per minute and then "punishes" you with 10 minutes of not listening anymore.

In /etc/inetd.conf, try this:

shell stream tcp nowait.1000 root /usr/sbin/tcpd in.rshd -L

Instead of this:

shell stream tcp nowait root /usr/sbin/tcpd in.rshd -L

For xinetd, there are more options (and more explicit):

cps

Limits the rate of incoming connections. Takes two arguments. The first argument is the number of connections per second to handle. If the rate of incoming connections is higher than this, the service will be temporarily disabled. The second argument is the number of seconds to wait before re-enabling the service after it has been disabled. The default for this setting is 50 incoming connections and the interval is 10 seconds.