Mailinglist Archive: opensuse (621 mails)

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Re: [opensuse] How to connect two servers through an Ethernet A/B switch and not change the upstream MAC addy?
  • From: Per Jessen <per@xxxxxxxxxxxx>
  • Date: Mon, 10 Jun 2019 20:29:25 +0200
  • Message-id: <qdm7i5$6f4$>
Lew Wolfgang wrote:

On 6/10/19 11:01 AM, Per Jessen wrote:
Lew Wolfgang wrote:

On 6/10/19 9:12 AM, Dave Howorth wrote:
On Mon, 10 Jun 2019 07:46:30 -0700
Lew Wolfgang <wolfgang@xxxxxxxxxxxxxxx> wrote:

Yes, a second MAC and port could be used, but then each server
would have different IP addresses.
Not so, it's a lot easier to use the same IP address for the two
machines if only one will be connected at any time.
Yes, I agree.  But upstream, over which I have no control, maps IP
addresses with MAC addresses.
This is not just ARP I take it?

Correct, not just ARP.

Also, static IP's aren't allowed, DHCP only.   It's also a
v4/v6 network, which complicates things.
Presumably you have DHCP clients on your primary ond your standby?
That's fine, but if you can't reserve one fixed address, that makes a
bit more problematic. The dual stack does not matter.

Yes, the servers run DHCP clients.  I use dnsmasq to control the
private subnet behind the servers.

Yes, I can't reserve a static IP addy.  MAC addresses are manually
entered into an LDAP database which is used to open a switch port when
that MAC appears on a port.  The DHCP-dispensed IP addy comes from
that same LDAP database.

Okay, so the usual method is out.

Hmm, any reason why you couldn't put a box between the upstream and your
two servers? I am thinking of using LVS, but you're going to need to a
fixed address. Unless you would want to redefine the LVS setup on
every change of address.
Actually, that could work. Put a box between upstream and your two
storage boxes. This box gets a DCHP address from upstream, your
storage boxes have fixed IPs, private network. The LVS setup has to be
reconfigured if the address changes, but that's doable.

Per Jessen, Zürich (15.4°C) - your owncloud, hosted in Switzerland.

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