Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
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For an installation of SAP on RHEL5 I'm facing the problem below when trying to open a telnet session to SAP:
Code:
sap02# telent sap02 51208
Trying 192.168.1.131...
telnet: connect to address 192.168.1.131: connection refused
telnet: Unable to connect to remote host: connection refused
In this case 192.168.1.131 is the correct IP address for the machine on eth0
The strange thing is that when I try:
Code:
sap02# telnet localhost 51208
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
....
It just works. Quite annoying, since I need it to go via the IP address. (If I telnet to that directly it fails as well with the connection refused error).
Just to make sure that the firewall isn't bothering me, I disabled it for the time being.
localhost is your computer and it always defaults to loopback address 127.0.0.1. SAP is mostly another machine. If you want to access it, its IP-host match information should be in your /etc/hosts file.
edit /etc/hosts file to include
Code:
192.168.1.131 sap02
then you may have to relogin or restart the network.
localhost is your computer and it always defaults to loopback address 127.0.0.1. SAP is mostly another machine. If you want to access it, its IP-host match information should be in your /etc/hosts file.
edit /etc/hosts file to include
Code:
192.168.1.131 sap02
then you may have to relogin or restart the network.
Btw, what is that 51208 thing?
Hi,
I'm trying both from the sap02 machine. So both telnet sessions end up on localhost. The issue is that the one coming form the loopback interface works and the one on eth0 doesn't.
And 51208 is some SAP port (I'm no SAP expert either; I just provide the Linux service to those SAP guys).
Ok, got your point. On my machine localhost works and so does the ip received by dhcp say 192.168.0.2. But on yours only localhost is pinging but not the ip received by dhcp (or manually configured ip).
Is your ip address given by dhcp service or you have manually configured the ip. If it is manually configured, then its information (as given in earlier post) should be in /etc/hosts. If it is automatic via dhcp, make sure you are able to access (ping/telnet) other machines in the network or the internet (if internet connection is enabled)?
In RHEL you should add the telnetd permission in /etc/hosts.allow
IIRC something like:
in.telnetd : 192.168.1. : allow
By default the remote access to some services is restricted.
Also you should check if the firewall is allowing the connections
to your SAP port, check /etc/sysconfig/iptables and add a line
like:
-A RH-Firewall-1-INPUT --dport 51208 -j ACCEPT
Then restart your firewall
/etc/init.d/iptables restart
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