IT人在工廠日記 – CBL 電郵封鎖問題 (2014/06/18)

最近兩個月,我公司的電郵系統地址經常被 列到 CBL 黑名單中,而限制了電郵的傳送,影響公司運作。CBL 黑名單的起因是網絡內某些電腦中了木馬病毒,例如:Conficker botnet,這會发送了大量的垃圾邮件给对方,因而被封鎖。我用過網絡掃描、更新殺毒軟件…等等方法,解決了問題,但是,一、兩星期後,又再被列到CBL 黑名单中,經常解決後又發生,是認真煩擾。

read more

Deploying Content Filtering to Manage Employee Browsing Behavior using Zywall USG 300 Firewall Device

  1. Introduction

In an enterprise network, there are various types of traffic. But most of the company’s Internet bandwidth is limited. All traffic will contend for it and may result in some important traffic, such as traffic getting slow or even starved. Therefore, intelligent bandwidth management for improved productivity becomes a matter of high concern for network administrators. To protect our network security, I am now using a Zywall USG 300 Firewall because its price is good and its performance is acceptable. I summarize its configuration in this document for your reference.

read more