Loopback! Loopback! @#!@#$@#$%

Loopback! Loopback! @#!@#$@#$%

Post by Joe Smulowi » Fri, 25 Oct 1996 04:00:00



Hi,

I've been struggling to get PPP going.  I succeed when using Minicom to  setup
the line and then doing "pppd -detach /dev/cua1"

However, when I try and use a chat script to do  this  I  get  something  like
(from memory):

 sent <stuff>
 received OK
 connect ppp0 <---> cua1
 serial line looped back
 terminating

What  am  I  doing  wrong?   One  person  said  I  have  to  set  up  the  PAP
stuff....why?

                                  Thanks.

------------------------------------------------------------------------------
 Joe Smulowicz               Hewlett-Packard                Tel: 508-659-3760

                       Andover, Massachusetts  01810        
      PGP fingerprint: 50 EA 8B 22 A0 59 60 D5  DD 4B 04 04 12 26 2E 16
------------------------------------------------------------------------------

 
 
 

Loopback! Loopback! @#!@#$@#$%

Post by Kalevi Hautanie » Sat, 26 Oct 1996 04:00:00


: Hi,

: I've been struggling to get PPP going.  I succeed when using Minicom to  setup
: the line and then doing "pppd -detach /dev/cua1"

: However, when I try and use a chat script to do  this  I  get  something  like
: (from memory):

:  sent <stuff>
:  received OK
:  connect ppp0 <---> cua1
:  serial line looped back
:  terminating

: What  am  I  doing  wrong?   One  person  said  I  have  to  set  up  the  PAP
: stuff....why?

No need for PAP if you can set it up manually. But the problem might be
the one Al Longyear writes in README.linux -file (in my machine /usr/doc/ppp).
Server does not have time enough to start the pppd process. The cure is to
add:

"&& sleep 5" to the end of your script.

Something like this:

/usr/sbin/pppd ... connect '/usr/sbin/chat ....  && sleep 5' &
--
                        Kalevi J Hautaniemi
----------------------------------------------------------------------------
Marjatankatu 12       |tel: +358-3-364-7446           |fax: +358-3-364-2476

FINLAND               |http://www.sci.fi/~khmi/       |On air:  OH3FG, KO4BC
----------------------------------------------------------------------------

 
 
 

Loopback! Loopback! @#!@#$@#$%

Post by Joe Smulowi » Tue, 29 Oct 1996 04:00:00


|However, when I try and use a chat script to do  this  I  get  something  like
| sent <stuff>
| received OK
| connect ppp0 <---> cua1
| serial line looped back
| terminating

I solved this.  In my chat script  (which  I  leveraged  from  /usr/doc/ppp  I
believe) there were three lines like this:

   TIMEOUT 3
   OK  ATZ        (reset modem)
   OK  ATH0       (hangup line)

The problem apparently was the ATH1 command.  The command  in  itself  is  OK,
but there was some timing issue involved.  I removed this  command  (it's  not
needed  anyway  since  it's  preceded  by a reset command) and all is well.  I
might have been able to get the ATH1 command to  function  if  I  preceded  it
with another TIMEOUT command, but I didn't bother trying.

------------------------------------------------------------------------------
 Joe Smulowicz               Hewlett-Packard                Tel: 508-659-3760

                       Andover, Massachusetts  01810        
      PGP fingerprint: 50 EA 8B 22 A0 59 60 D5  DD 4B 04 04 12 26 2E 16
------------------------------------------------------------------------------

 
 
 

1. problem with ethernet loopback test using loopback plug/stub: receiving socket not seeing packet.

we are writing socket application to send UDP packets out from eth1
and loop it back to
the same interface using loopback stub to verify the hardware without
using external
devices/ports.  The sending and receiving port are the same.

our target machine has eth0 configured as 15.6.xx.xx and  eth1
configured as 16.6.6.6.

the listening socket is listing on all ip.

.

When we looked at the packet in the tx code of the driver, we have
observed that the packet passed down from the ip stack has the same
MAC address for both source and destination.  Also when packet is
returning, its ip source and destination are the same as the
transmitting packet, which is to be expected.

The outgoing packet on eth1 has ip address of 16.6.10.10.

1.      Is this type of loopback possible under linux?
2       Is it better to send raw packet, or should UDP work as well?
3.       is there a similar code that we can leverage?
4.  the returning (incoming) packet is lost after the driver passes it
to the ip stack. The receving socket is not able to retrieve packets
the driver receives.
What could be some of the issues?

Thank you in advance.

2. Console Apps

3. loopback != loopback.uwc.edu (?)

4. possible cache aliasing problem with O_DIRECT?

5. loopback to hostname

6. FreeBSD 4.4 Install Problems

7. Multicast on loopback?

8. SCO Security and Windows clients

9. PPP leased line loopback problem, etal

10. fake loopback route

11. :All of your loopback devices are in use.

12. Apache - Netscape - Loopback problem

13. loopback device - documentation?