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Subnet Mask

 
robert70
Valued Contributor

Subnet Mask

I have an Alpha DS20E running VMS 7.3-2
This has a DE600 network card installed.
The Subnet Mask of this TCPIP setup is 255.255.255.0

When a 2nd DS20E (containing a DE500 network card) is restored with the identical system image of the 1st Alpha there are problems when starting up TCPIP. (eg You cannot Ping the 2nd Alpha IP addresses.) The 2nd Alpha is on a totally seperate network.

Any Ideas?

Why does the differing types of card have an effect on
6 REPLIES 6
Robert Gezelter
Honored Contributor

Re: Subnet Mask

Roger,

It would be helpful if more complete information were supplied (e.g., which TCPIP package, and the full characteristics of the interfaces on BOTH systems -- in HP TCP/IP the results of the SHOW INTERFACES/FULL command). A display of the routing information is also useful (e.g., TCPIP SHOW ROUTE).

There are many reasons the systems may be unable to establish communications. The subnet mask is a possibility, but not necessarily the most likely suspect.

Possible problems that I have seen in similar situations include duplicate IP addresses, filtered networks, disconnected networks, and a variety of other causes.

The only way to disambiguate what is happening is to review the details in order to ascertain where the problem lies.

- Bob Gezelter, http://www.rlgsc.com
Hoff
Honored Contributor

Re: Subnet Mask

This looks to be a standard case encountered when reloading an OpenVMS box with a different network controller configuration; swapping network hardware configurations around does mean you'll usually need to re-run the stack-specific configuration.

Run the configuration tool for the particular IP stack.
Duncan Morris
Honored Contributor

Re: Subnet Mask

Roger,

the DE600 device would be VMS device EIA0, IP interface device IE0.

the DE500 device would be VMS device EWA0, IP interface device we0

On the second DS20e you will not have a configuration for we0 - only one for the non-existant ie0.

As Hoff says, run your TCPIP configuration utility.

Duncan
jjinva
Advisor

Re: Subnet Mask

I ran into this problem when restoring a System Image from one System to another. It turned out that the restore branded the new network card with the old network cards Ethernet Address. You can use the UCX/TCPIP command "show inter/full" to check for conflicts. Not sure if this is your problem but something to look at.
Hoff
Honored Contributor

Re: Subnet Mask

> I ran into this problem when restoring a System Image from one System to another. It turned out that the restore branded the new network card with the old network cards Ethernet Address. You can use the UCX/TCPIP command "show inter/full" to check for conflicts. Not sure if this is your problem but something to look at.

Which is the standard case encountered when reloading an OpenVMS box with a different network controller configuration; swapping network hardware configurations around does mean you'll usually need to re-run the stack-specific configuration.

Run the configuration tool for the particular IP stack.
Steve Reece_3
Trusted Contributor

Re: Subnet Mask

A DE500 is not the same as a DE600. If they were, they'd both have the same number!
You have two choices:
- rerun the TCP/IP config as suggested already;
- Get a DE600 for the second system and replace the DE500 with it.

Even if you replace the DE500 with a DE600, you're still relying on the hardware being presented in the same way (i.e. that the card that was IE0 is still IE0)

Upshot?
You're probably still best (and it's cheapest) rerunning the TCPIP$CONFIG and resetting your address to be on the right ethernet card.