Introduction

One of the most important aspects of network security is to establish who is responsible for what. It is a matter of fact that the Internet is an increasingly hostile place and that Sites connected to the Internet must address the many potential threats to the integrity of their networks, systems, data and applications. ClydeNET is basically a transit network designed to operate as fast as possible without placing any unnecessary obstacles in the data communications paths. It is therefore essential that sites recognise that the security of their networks, systems, data and applications are their own responsibility. However since all the ClydeNET core and site routers fall under the same centralised management domain there is scope for a consistent set of basic security policies applied as security access control lists (ACLs) to all ClydeNET routers. These ACLs implement a good balance between accepted best practices and the experience of the ClydeNET operations team; the current version of the default router ACLs are presented below for inspection. Of course ClydeNET sites may request changes to their default router ACLs or indeed that the ACLs be removed entirely because of local security policies and measures. ClydeNET sites are strongly encouraged to establish a Computer Emergency Response Team (CERT) contact and subscribe to the UKERNA security e-mail list. ClydeNET sites may obtain additional security advice from the following sources:

ClydeNET Operations Desk – cod@clyde.net.uk
UKERNA Computer Emergency Response Team

Router Access Control Lists (ACLs)

Each ClydeNET site router has been configured with two security ACLs. The first acl applies to traffic coming from ClydeNET to the site and the second acl applies to traffic coming from the site to ClydeNET. Full details of these ACLs can be found in each sites ClydeNET Information Pack