Given the limited disk space allocated to a Zeus Traffic Manager Virtual Appliance you might need to free some space to perform certain tasks. This is usually most visible when performing upgrades where you might be presented with the following message: Read more...

If you notice that warning messages that include "License key bandwidth limit hit" are being emitted to your traffic manager's event log then you are hitting your license's configured bandwidth limit.

If your Zeus Traffic Manager is using loopback virtual servers and you have a bandwidth limit you need to remember that your traffic manager will reach that limit more quickly. Read more...

As a fun experiment and to highlight ZXTM's flexibility in hosting applications I decided to make ZXTM speak with the help of an API provided by an interesting company Twilio. Read more...

Accessing ZXTM's Control API from Scala is a relatively straightforward process. It is almost identical to the process you use for Java. Read more...

There has been a lot of talk over the past few years about new and different languages targeting the JVM as their runtime platform. Scala has been one of the most high-profile languages in the JVM vanguard. Most notably, in the past year Twitter has announced that it is migrating away from Ruby on Rails to Scala because of RoR's lack of scalability. Read more...

An alternative method for using ZXTM's Control api with Ruby is to use the soap4r SOAP implementation. I have found this to be quite useful when writing scripts for testing recently. Soap4r can be found at,

http://dev.ctor.org/soap4r Read more...

The Zeus GLB (Zeus Global Load Balancer) manual introduces the Zeus GLB software, describing deployment considerations, the installation procedure and common configurations for disaster recovery and load-balancing scenarios. Read more...

ZXTM GLB 2.1r1 was released on 26th January 2009 via customers' download pages and is now available for evaluation. Read more...

As websites grow, the structure of their URLs can change dramatically. This makes things much more manageable from an operational point of view, but what can be done about all of those links people have to that website? Ideally, we would like to ensure that people with the old link are presented the most relevant content on the new website. When the web-application is large or under the control of a different department, it may be difficult to change things. Well TrafficScript™ comes to the rescue once again. Read more...

Upgrading from SLES (Suse Linux Enterprise Server) version 9.x to version 10.x has a side effect of altering the order that startup scripts are run. This can result in ZXTM being started before the networking on the machine has been initialized and can result in issues including ZXTM reporting itself as being unlicensed.

It is also possible for this problem to occur if you have turned ZXTM off then on again via the chkconfig command. Read more...

The new release of ZXTM includes a battery of networking improvements. The ability to control how internal traffic is routed onto external networks is now configurable through the administration interface amongst other things. I'll briefly explain what you need to consider when setting this up. Read more...

Due to a known driver issue when controlling the IPMI functionality on ZXTM appliances, occasionally the following error may appear in the event logs.

Channel 1 is not a LAN channel

Should this error appear and it is not accompanied with an error displayed on the Diagnosis page then there is nothing to be worried about. It is most likely to appear during the initial configuration stage.

Zeus is working on resolving this issue and a fix is expected to be included in a future release of ZXTM.

The ZXTM Appliance uses the rp_filter module to protect against IP packet spoofing from local networks. This module drops traffic that arrives on an unexpected interface, so it stops an attacker on one network from spoofing packets that appear to come from a different network.

However, if you have multiple IP addresses on the same subnet and you place them on different interfaces, then the spoofing protection can mistakenly drop valid packets. This only affects packets that originate from the local network, and it is only a potential problem if you have IPs on the same subnet configured on different interfaces. Read more...

Often people ask how our Bandwidth Management feature works, so that they may understand more clearly how deploying it will affect their traffic.

ZXTM's Bandwidth Management feature is built on top of Linux's Quality of Service(QoS) infrastructure. In particular it interfaces with the Hierarchical Token Bucket(HTB) and Stochastic Fair Queueing(SFQ) Queueing Disciplines. Before I talk about ZXTM's part I'll explain a little bit more about the queueing disciplines I have mentioned. Read more...

The manual describes how to access the ZXTM Control API using Java. This example will show in more detail what can be done with the API and the Java language by replicating the UI Wizard "SSL Decrypt a service". Read more...

Having fielded a few questions about this here are the details in all their gorey glory.

Supported distributions: All of them! The distribution is mostly irrelevant though with most modern distributions this feature should just work "out of the box". All that is needed is the correct kernel and the iproute package. Read more...