AIXDieSmittyDiePartI

How to really mess up with smitty and network config

I feel very stupid right now, so I hope this is going to be a warning to all AIX administrators out there: DO NOT TRUST SMITTY!!

Here is the problem:

Originally, the machine only had one network card (we'll call it en6) configured and active. This is a production server, connected to, and used by, a number of clients. And these people do not like to be interrupted while they work.

The problem: the machine has to be moved from one site to another. And the other site requires several network cards to be configured: one for production use, another for administration and a third for backups over the network.

Simple enough: use smitty tcpip to configure the network cards, right?

Wrong. You see, there is the small matter of the hostname. Like an idiot, I entered all the correct information in smitty... But without changing the hostname!! I simply used galactus everytime, for all interfaces.

But, says the astute reader, there is no reason that this will mess things up? Right? Right??!!??

Wrong again! You see, smitty, this incredible piece of manure, silently inserts an entry in /etc/hosts... for every single interface!!.

Here is an example:

# grep -i galactus /etc/hosts
10.1.1.10              galactus
10.2.0.100             galactus
10.3.0.100             galactus
10.4.0.100             galactus

The result, unfortunately, is entirely predictable: with its network configuration completely messed up, poor old galactus became unreachable by half the planet Earth... Including the demanding clients mentioned above.

Now, of course, if smity was smart about it, he could perform a simple check in /etc/hosts and warn you that an entry by the name galactus already existed in that file... But, of course, it does not do that!

At the very least, it could pop a warning before messing any system configuration file, something like, you know:

+----------------------------------------------------------+
| WARNING: the file /etc/hosts is now going to be          |
| modified to contain the selected hostname.               |
| Are you sure you'd like to proceed?                      |
| - Press [ENTER] to continue and apply changes.           |
| - Press any other key to cancel.                         |
+----------------------------------------------------------+

But NO, that would be too simple, right? Instead, it just goes ahead and messes silently with your system configuration!!

And don't tell me that you have to know what you are doing, since smitty is perfectly capable of displaying warnings for other operations.

"IBM: we know what's good for you."

You have been warned.

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