The ISC let know that the central RU network will be down in the night of Monday December 12 22:00 till Tuesday morning 03:00 because the RU firewall will be replaced. From 22:00 hours RU-central services such as Exchange (e-mail and calendar), BASS, Osiris and Blackboard will not be available. From 23:00 hours no traffic through the RU firewall will be possible, the RU will then be disconnected from the Internet. Internal wired FNWI traffic will not be hindered. Internal and external telephony will not be hindered too. If there are serious objections to this maintenance for ongoing research, one can contact us.