Note Interne CCR 2016

CCR-53/2016/P: DA-DA: A Method to Ease IPV6 Rollout at Non-SLAAC Sites

Francesco Prelz

INFN Sezione di Milano


The exhaustion of IPv4 addresses is handled in version 6 of the IP suite of protocols via a massive (x296) increase of the available address space. EUI-64 based automatic addressing (SLAAC) becomes possible, but it is not the only option for address allocation in this wide space - in certain cases it may not be an option at all.
A mechanism (DA-DA: DNS-driven Allocation of DHCPv6 Addresses) is proposed to provide public addresses to dual-stack IPv4/v6 hosts via DHCPv6 and to populate the DHCPv6 configuration database in the course of the IPv4 ® IPv6 transition. Address assignment is driven by the DNS contents only and (similarly to SLAAC) provides hosts with access to the public IPv6 Internet with no user intervention. A reference implementation (in the form of an ISC DHCPv6 patch) is available.
 

CCR-52/2016/P: Configuration of User/Node Affinity in a Sendmail+Dovecot+Squirrelmail E-mail Cluster

Michele Bensi1, Stefano Barberis2, Massimo Mezzadri2, Francesco Prelz2

1) Università degli Studi di Milano, 2) INFN Sezione di Milano


The storage of user email boxes on a shared filesystem and their read/write access on multiple cluster nodes requires special care to benefit from file persistence in the filesystem cache on each node and to prevent system response to be significantly degraded by frequent file synchronisations onto physical storage. The simplest measure towards this goal is to divide access to nodes on a peruser basis, while keeping the cluster failsafe. In this paper we share a few nonobvious details for the configuration of such user/node affinity in sendmail, dovecot, squirrelmail.
 

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