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Old 03-29-2006, 01:31 AM   #1
libregeek
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Registered: Oct 2005
Posts: 47

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Connecting two machines using Null Modem Cable


Hello all,
I am trying to get connection between two machines using PPP. I am able to pass the echo/cat test as described in http://linux-ha.org/GettingStarted

After testing the link I tried to run pppd on both the machines(CentOS-4.3 and Fedora Core 3).

Machine 1 (centos):
PPP version : ppp-2.4.2-7
Code:
pppd -detach crtscts lock 192.168.1.10:192.168.1.20 /dev/ttyS0 38400  &
The output on this machine is as follows:
Code:
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS0
Deflate (15) compression enabled
local  IP address 192.168.1.10
remote IP address 192.168.1.20
On Machine 2(fedora) :
PPP version is ppp-2.4.2-6.4.FC3
Code:
pppd -detach crtscts lock 192.168.1.20:192.168.1.10 /dev/ttyS0 38400 &
the log on machine 1:
Code:
Connect: ppp0 <--> /dev/ttyS0
Deflate (15) compression enabled
local  IP address 192.168.1.20
remote IP address 192.168.1.10
But when I ping both the machines it doesn't work.
In machine 1:
Code:
[root@r223a ~]# ping 192.168.1.20
PING 192.168.1.20 (192.168.1.20) 56(84) bytes of data.

--- 192.168.1.20 ping statistics ---
5 packets transmitted, 0 received, 100% packet loss, time 4014ms
and in machine 2:
Code:
[root@cobra kronolith]# ping 192.168.1.10
PING 192.168.1.10 (192.168.1.10) 56(84) bytes of data.
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted

--- 192.168.1.10 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 1999ms
Is there anything I went wrong? Somebody please guide me.

regards
Manilal
 
Old 03-29-2006, 06:40 AM   #2
demian
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Registered: Apr 2001
Location: Bremen, Germany
Distribution: Debian
Posts: 303

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The ppp connection seems fine. "ping: sendmsg: Operation not permitted" means iptables is blocking icmp packets on 192.168.1.20 from even leaving the machine.

Last edited by demian; 03-29-2006 at 06:42 AM.
 
  


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