Configuring multiple IP addresses on VLAN interface using ifupdown

[Steffen Dettmer <steffen.dettmer@gmail.com>]

Hi,

I'd like to configure multiple IP addresses to a VLAN tagged interface. I tried

auto eth3.107
  iface eth3.77 inet static
  address 10.0.5.15
  netmask 255.255.255.0
  iface eth3.77 inet static
  address 10.0.5.16
  netmask 255.255.255.0

but I get an error message that ifup tries to configure the VLAN
interface twice, but the addresses are set.

When I remove the second "iface eth3.77 inet static" line, which
should be correct according to my understanding of "man interfaces",
where it is not forbidding to pass multiple "address" directives in a
stanza, I get an error about unexpected "address" line and the
addresses are not set.

First I thought "ifup" would be a shell script, but apparently
ifupdown uses source code generation to generate Perl code from some
"noweb" code and uses the generated Perl code to generate C code which
then is compiled using a generated Makefile -- all this is not easy to
read / understand, so I decided to write a mail here hoping someone
can enlighten me :)

Best regards,
Steffen