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bsdnazz Absent Member.
Absent Member.
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Is removing an network interface

Hi,

I have a number of OES2 SP1 (soon to be SP2) servers with two network interfaces on them. One is for our internal network (using RFC1918 addresses) and the other is for our external network.

We will soon be changing our external network addresses the OES2 SP1 servers don't actually need
an interface on the external network so I'd like to remove those interfaces.

Do I need to do anything more then unconfigure the network interfaces in YAST2?

NB the servers are all virtualised on ESX V3.5U5 but I don't think that has much impact here.
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Michael_Fleming Absent Member.
Absent Member.

Re: Is removing an network interface

Do you have any services running on those interfaces? Check NRM ect to make sure.

If nothing is using the external interface then its good to remove.
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bsdnazz Absent Member.
Absent Member.

Re: Is removing an network interface

When the servers were installed both interfaces (internal and external( were configured and most (if not all) services are running on both interfaces.

Unless I'm missing something obvious, I can't find an NRM page that lists the interfaces which which services are running on them.

netstat -ln which lists listening services with numeric addresses show that a number of services are bound to both interfaces.

The main TCP services are: svrloc, ncp, port 8028, port 8030. The main UDP services are netbios-ns, netbios-dgm and ncp.


Am I right in thinking that I have to unconfigure each of these services manually rather than being able to rely on YAST2?
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Michael_Fleming Absent Member.
Absent Member.

Re: Is removing an network interface

Sorry I was thinking of NW's IP address management section of NRM. Linux doesn't have it so you will have to find a similar way of reconfiguring the services to listen only on the internal address.
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Knowledge Partner
Knowledge Partner

Re: Is removing an network interface

I'm going to guess here, but when you installed OES2 on the servers, were both NIC's activate and have IP's on them? Or did you "configure" the secondary NIC AFTER the installation?

If the latter, then you should be able to simply remove the IP configuration from the 2nd NIC

IF both were enabled and possibly you chose the external IP, then you'll have to get a list (like Michael suggested) of what's running on which IPs to avoid accidentally breaking something.

If anything will break, IMO, it'll be the OES2 stuff vs. the Linux stuff (most Linux things bind/run on all IP's. IMO, MOST of the OES2 stuff will as well, but not necessarily).
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bsdnazz Absent Member.
Absent Member.

Re: Is removing an network interface

Hi kjhurni,

The two network cards were present and had IP addresses configured during Linux configuration prior to installing OES2 SP1. It was done in one installation process.

Search round the OES config files the IP addresses do appear in a few places. I suspect I'm going to have to edit the config files and reboot. There will probably be a few eDirectory entries to edit/delete.

I'm OK with the Linux side of things a most (if not all) service bind to all interfaces present and don't explicitly specify IP addresses.
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Michael_Fleming Absent Member.
Absent Member.

Re: Is removing an network interface

OES IP address management can be tricky on Linux.

I would recommend checking out the cool solution for IP address change as that should tell you all the places to look.
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bsdnazz Absent Member.
Absent Member.

Re: Is removing an network interface

While I head off to search the Cool Solutions, does anyone have a link to the article?
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Michael_Fleming Absent Member.
Absent Member.

Re: Is removing an network interface

I was going to lmgtfy but here it is 🙂

Novell Documentation
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bsdnazz Absent Member.
Absent Member.

Re: Is removing an network interface

Thanks for that Michael. I did find that too and it's quite useful. The main problem being that it relates to changing an IP address rather than removing one.

I ended up doing most of the work manually and editing the various configuration files.

The command 'netstat -l' is useful to list the ip address/port combinations on which various programs are listening and 'find /etc -print | xargs grep <IP address fragment>' was very useful to find were services were configured to use different addresses.

Many of the service simply bind to all available interfaces so nothing needs to be done. The rest I edited and all's well so far after a reboot.
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Michael_Fleming Absent Member.
Absent Member.

Re: Is removing an network interface

ok cool. Hopefully nothing goes bump from it 🙂
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