Debian: network not working after suspend

The problem:

When resuming from suspend, the network connection is lost. This happens whether using network-manager or /etc/network/interfaces. My network interface is Realtek r8169 (I found this with lsmod).

In /var/log/pm-suspend.log, I get the following message:

/etc/pm/config.d/unload_modules: SUSPEND_MODULES: not found

Solution:

1. Install packages acpitool and firmware-realtek.
2. Make sure the file /etc/pm/config.d/unload_module exists, and add this line:

SUSPEND_MODULES="r8169"