Hello, Most software allows you to configure the IP the software binds to. Aside from that, I am not aware of of any other methods, provided by clustering. (The IP is simply added 'inside' the IP stack of the host) In your case that would mean configuring the source IP in your monitoring module (check_snmp) or the tool used inside the module (snmpget). Snmpget should be configurable through snmp.conf with the following option: clientaddr [<transport-specifier>:]<transport-address> Specify source address used by command-line tools, see snmpcmd(1) , and by snmpd when sending notifications. See: http://www.mail-archive.com/net-snmp-users@xxxxxxxxxxxxxxxxxxxxx/msg08109.ht ml In case of an iptables solution, this might help: http://fixunix.com/snmp/65274-snmpget-snmpwalk-using-virtual-ip.html Regards, Kit -----Original Message----- From: linux-cluster-bounces@xxxxxxxxxx [mailto:linux-cluster-bounces@xxxxxxxxxx] On Behalf Of Bernd Broermann Sent: donderdag 19 augustus 2010 11:26 To: linux-cluster@xxxxxxxxxx Subject: IP Source NAT Hello Senol, Hello all, I my special case I want to setup a 2 Node Active/Passiv failover Cluster with nagios ( nrpe/snmp ) as a service. ClusterNode1IP - -> vIP ----------- Clients (connects only allowed from vIP) ClusterNode2IP - The nrpe and snmp Agents only allow connects from the virtual IP of the Cluster. An iptables nat rule should do that for these ports. But is there a best practice ? Thank you Hi Bernd, your comments too much close but; - if u are build two node fail-over (as Acrive-Passive) you can give to vIP to active node starting, - if u are using two or more server at the moment (for Load Balancing) then your keywords "ipvsadm" and "Direct Routing". 2010/8/18 Bernd Broermann <bernd broermann com> Hello, How can I define a resource to make all outgoing network packets appear to be the virtual IPaddress ? I mean something like the "ipsrcaddr" resource in OCF:heartbeat. Thanks for answers, bernd -- Linux-cluster mailing list Linux-cluster redhat com https://www.redhat.com/mailman/listinfo/linux-cluster -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3082 - Release Date: 08/19/10 20:35:00 -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster