Cluster IP address

[Kitti Thanapuasuwan]

I have two AlphaServer running OpenVMS v7.2 with cluster hard drive. The second machine is for backup. I have application connect to vendor outside using TCP/IP. So I want to set one common IP address to connect to them. Vendor will not know the appliaction is connected with which machine.

My 1st machine IP is 192.255.5.41 and 2nd is 192.255.5.43. I want to use IP 192.255.5.45 to connect to vendor.

The second question, Any communication between our machines and vendor, they will see only IP 192.255.5.45 from/to us. Whenever I log-on to any machine and do some command e.g. ping, telnet, they will see it come from 192.255.5.45 instead the actual IP.

Thank you in advance for your help
Kitti

[Jan van den Ende]

Kitti,

sorry to disappoint you, but it looks like what you want is an OUTGOING ALIAS.
That functionality is well known in DECnet context, but IP is ignorant of that.
In the world of IP, if you have redundant network cards, yuo do not even have a sending SYSTEM -- you have (the IP of) the sending NETWORK CARD!

But, if anyone HAS a way to do it: I am also interested!

Proost.

Have one on me.

jpe

[Richard Brodie_1]

It's probably cleanest to use a hardware router to do this; you have pretty much reinvented NAT. I'm sure the folks over on the networking forums could suggest something suitable.

[Andy Bustamante]

Adding to Richard's response, this could be done with firewall rules depending on your network configuration. With TCPIP 5.4, using a service address and a server management address can make system management easier and application delivery more flexible. This is especially true if you don't have control over the network.


Andy

[Hoff]

One approach would involve network address translation (NAT); where you have several nodes behind one address. (NAT can get really ugly, as it has to track outgoing requests with responses; you don't want your return traffic ending up at the wrong host. If you can avoid NAT, do so.)

The failSAFE IP mechanism is the closest to what you want here, though only one node will be active with that address at any given time. failSAFE allows multiple controllers to be ready to take over a particular IP address, though only one of these can be active at a time.

Can you get the vendor to allow a range of addresses? 192.255.5.43/2, for instance. Or move to a VPN or another mechanism not based on originating IP address?