The problem is, Debian's /etc/network/interfaces is outdated. It doesn't have a good notion of dependencies, it can't really cope with interfaces having IPv4 and IPv6 addresses, bridge support is flaky and so on.
Most of my network configuration ends up in pre-up and post-down scripts.
Posted Apr 4, 2012 23:16 UTC (Wed) by rleigh (subscriber, #14622)
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Have you tried the new ifupdown in experimental? If not, it might be worth a try (but an updated version will be going into unstable in the next few days if you want to wait). This fixes a lot of long-standing issues.