Mapping stanzas in interfaces file not working

[Chris Eisley <chris@cepheus.net>]

Hello,

I'm trying to switch over from commenting/uncommenting relevant iface
stanzas (man pages call them stanzas, so no snipes about my lack of
understanding of the word) in /etc/network/interfaces to using the
mapping mechanism described in the interfaces man pages.

The problem is that when I put the mapping entry in, ifup gives the
error "Ignoring unknown interface eth0=eth0."  The script I designate in
the script line of the mapping stanza is never being executed and of
course the eth0 interface isn't being configured.

Here's what I'm trying.  The iface lines you see below all work
perfectly when they use physical interface names instead of logical ones
(ie eth0 instead of eth0-whatever); in the past I was simply
uncommenting the one I wanted to use at the time.

# Logical mappings for Ethernet card
mapping eth0
        script /etc/network/show-role.sh -q -l
        map INTERNAL-WAP        eth0-internal-wap
        map INTERNAL-CEPHEUS    eth0-internal-cepheus
        map EXTERNAL            eth0-external
        map DHCP                eth0-dhcp

I then have corresponding iface entries with logical interface names:

# Ethernet card acting as external interface on 192.168.1/24 net
iface eth0-external inet static
        pre-up /etc/rc.firewall
        down /etc/rc.firewall
        dns-nameservers 172.16.0.1
        dns-search cepheus.net
        address 192.168.1.2
        gateway 192.168.1.1
        network 192.168.1.0
        broadcast 192.168.1.255
        netmask 255.255.255.0
        name Ethernet LAN (External Interface)

# Ethernet card acting as internal interface on 192.168.2/24 net
iface eth0-internal-cepheus inet static
        address 192.168.2.1
        network 192.168.2.0
        broadcast 192.168.2.255
        name Ethernet LAN (Internal/Cepheus Interface)

# Ethernet card acting as internal interface on 192.168.2/24 net
iface eth0-internal-wap inet static
        address 192.168.1.2
        network 192.168.1.0
        broadcast 192.168.1.255
        name Ethernet LAN (Internal/WAP Interface)


-- 
Chris Eisley <chris@cepheus.net>