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Understanding and Troubleshooting Videoconferencing Networks - UW Course

August 31, 2010

The University of Wisconsin-Madison will offer its very popular course Understanding and Troubleshooting Videoconferencing Networks on November 2-3, 2010. The course will be held on the University campus in Madison, WI and will also be available via live videoconferencing.

By attending this course, you will master the H.323 standard and embedded protocols and then extend this understanding to SIP based and proprietary systems. Topics include:

• H.323 standard: components and functions • Call signal processing and audio/video data flow • QOS: options, implementation issues • How ITU H.323 relates to IETF SIP and MGCP/Megaco • Options for handling firewalls in the network • Addressing and directory services • Performance characteristics of various audio and video codecs • Network security and other advanced features • High definition videoconferencing options and content display • Troubleshooting and analysis tools and techniques • Understanding audio and video compression technology

Your course instructor, Gary Thom, is President of Delta Information Systems, a recognized expert in the field of videoconferencing, and the author of versions 1 & 2 of the H.323 standard.

Reserve your space today! Call toll-free 1-800-462-0876 Or online at http://epdweb.engr.wisc.edu/courseL800

Permalink: Understanding and Troubleshooting Videoconferencing Networks - UW Course

Symantec is Blocking Ericsson and Others

May 10, 2010

We have reported several times about our email server being blocked by spam-fighting organizations. While most organizations are quick to respond, some refuse to address the issue and others refuse to even talk to us about the issue. What's most frustrating is that our mail server does not send spam.

We are still blocked by SORBS, who told us without hesitation that, until Amazon pays them money, they're not going to unblock our address. The way they phrased their demands, it sounded like extortion to us. Apparently, they block all Amazon IP addresses and, since our mail server operates in the Amazon EC2 cloud, customers of SORBS are unable to participate on mailing lists we operate on Packetizer, specifically lists.packetizer.com.

More recently, Symantec has become a problem. Sadly, this is an organization that we could generally consider more reputable than others. Unfortunately, the company decided to block our mail server by assigning it a 'bad' reputation. This has affected Ericsson and perhaps other companies that would normally participate in ITU-T SG16 activities.

We tried contacting Symantec and they told us that they will not correct the problem, since we are not their customer. We've tried to explain that their customers are entirely unaware of the fact that they are being blocked, but they did not care. We alerted Ericsson once we became aware of this issue, but we do not have any way of knowing if other companies are blocked due to use of Symantec's Brightmail or other spam blocking services or products offered by Symantec.

If you attempt to join a mailing list on Packetizer and never get a response indicating that you successfully joined and your company uses Symantec products or services, then Symantec may be to blame.

Permalink: Symantec is Blocking Ericsson and Others

OpenID Gaining Widespread Support

March 27, 2010

OpenID is a web technology that allows a user have a single user identity and password that may be used to access any number of web sites, thus removing the age-old problem of having to maintain separate login and passwords for all of the various accounts on has on the Internet.

It is now supported by many web sites, including Google, Slashdot, Blogger, Flickr, Yahoo, Orange, MySpace, WordPress, AOL, and Facebook. Some of those organizations are 'identity providers', while some are end-user sites that rely on the identity providers to allow users to gain access to site content.

We produced an OpenID identity server software package for anybody who might be interested in running their own identity server. Perhaps equally important, though, is that we also added support to Packetizer Forums so that one may use OpenID to login, post questions, or reply to questions.

We hope OpenID support proves to be a popular and valuable service to the Packetizer Community.

Permalink: OpenID Gaining Widespread Support

H.325 Experts Progress Standard through Electronic Meetings

November 29, 2009

At the most recent meeting of ITU-T SG16, the H.325 experts decided to initiate a series of electronic meetings in order to help progress the work. For those interested in participating in the creation of this exciting new multimedia system, see the meeting notice posted on the h325-design mailing list.

Permalink: H.325 Experts Progress Standard through Electronic Meetings

IP Address Blacklisting Still an Issue

November 21, 2009

As we reported earlier, a number of spam-fighting organizations decided to block part or all of Amazon's EC2 service. This caused significant disruption to the mailing lists that we operate on Packetizer's mailing list server, including which provides list services for those working on ITU-T related work.

This past month, Spamhaus decided to block all of Amazon, in spite of the fact that we had previously submitted our IP address for removal at Spamhaus. That resulted in about 30 people getting kicked off of various mailing lists. So, if anybody reading this is wondering why you have not received email in a while related to H.323, H.325 or other protocols, Spamhaus might be the reason.

Fortunately, Spamhaus and Amazon quickly reached an agreement on how better coordinate in order to ensure that all of Amazon's EC2 IP addresses are not blocked again. To that end, Amazon now requests all mail servers to be registered with Amazon, which of course we did immediately. Amazon reviewed our request and granted authorization to use the server in order to transmit email.

On or about the same time, unfortunately, Amazon was also listed in MAPS and SORBS, two other spam-fighting organizations. We visited the MAPS web site, provided our IP address, and were almost immediately removed from their list.

SORBS, on the other hand, has been a real problem. The organization absolutely refuses to unblock Amazon EC2 or our individual address. We contacted SORBS and, while they were responsive, their reply was less than satisfactory. One of the more polite statements was:

You are not required to make a donation for delisting as the entry was not generated because of your actions, however the listing will not be removed until your service provider terminates the spammers or makes the required donation.

That is perhaps the closest thing we have ever seen to extortion. Sadly, while we continued to have a friendly dialog, after 20 days our mail server is still blocked by SORBS. It would appear they have absolutely no intention of removing Amazon EC2 and we do not believe that Amazon has any intent to work with them either. We can only suggest that if your company is using SORBS, you consider using an alternative blacklisting service.

Permalink: IP Address Blacklisting Still an Issue

IP Address Blacklisting Issues

September 24, 2009

Spam has been a problem for years and it seems almost impossible to address. Two years ago, Packetizer was receiving thousands of spam messages per day and we were forced to implement various spam blocking technologies, including blacklisting IP addresses. As much as we hated to do that, it became necessary, as it was otherwise impossible to find and read the legitimate email. We also began employing technologies like SPF and are also now using DKIM, digitally signing every message transmitted by our mail server.

It was never our intention to block legitimate mail servers and as issues were brought to our attention, we took immediate steps to resolve the problems. Our servers would provide a response back to senders when they are blocked and we also provided a tool where anyone can query to see if their server is blocked.

In the spring of 2009, our mail server was re-located and is now running inside Amazon's EC2 cloud service. We were assigned a static IP address and have been using that same IP address for all outbound mail since. Initially, we were somewhat disappointed to learn that our server was actually blacklisted on a few Internet blacklists. However, we were quickly able to resolve those issues with the more legitimate blacklisting organizations, such as Spamhaus and Spamcop. Unfortunately, UCE PROTECT was not very willing to cooperate. After a month of negotiating, they finally agreed to remove us from their list.

The reason our server was on their list is because we run mailing lists and some bots subscribe (or attempt to subscribe) to mailing lists using bogus addresses, to which our server politely responds with a welcome message, assuming the message passes the SPF test. (We are presently not enforcing DKIM, but will once this is generally practiced.) Unfortunately, UCE PROTECT treats those messages as spam messages and then places our server on the blacklist.

Packetizer was not listed on UCE PROTECT's blacklist for several months, but it appears we are now listed again. We attempted to contact UCE PROTECT via email and were blocked. So, there appears to be little or nothing we can do: we cannot even discuss the issue.

Unfortunately, many people on the H.323 Announce list and other mailing lists are not receiving messages and, in some cases, are being removed from mailing lists due to message rejections. Please note that this is not our fault and if you find yourself unsubscribed, definitely feel welcome to subscribe again. If your service provider or employer is using UCE PROTECT, you may wish to ask them to stop using the service.

Permalink: IP Address Blacklisting Issues

Announcing Packetizer Forums

August 25, 2009

With the increased focus on videoconferencing and VoIP communications, there has also been an increase in the number of questions people have about implementation, configuration, deployment, troubleshooting, etc. Some questions are rather straight-forward, while some really require the expertise of people who have been working in the area for a while.

Packetizer is a community-driven web site that operates a number of different mailing lists and publishes a lot of material in an effort to try to help people build, design, and deploy multimedia communications technologies. On Packetizer, you will find high-level overviews about VoIP, frequently asked implementation questions and details, tutorials, and so forth. However, even with all of the resources already available, there seemed to be something more needed.

After collaborating with a number of people in the community and taking a poll, it was decided that a new discussion forum would be useful. As a result, we created a new site called Packetizer Forums, which is open to everybody to ask questions, provide answers, and to learn. Oh, and having fun never hurts.

We hope you enjoy the added service!

Permalink: Announcing Packetizer Forums

H.323 and H.325 Moving Forward

June 18, 2009

The increased focus on videoconferencing has brought with it a renewed interest in H.323. While this is not entirely surprising, given that H.323 was specifically designed to enable video communications over packet-switched networks, it is nonetheless an indication that H.323 is still a major force in the market.

Over the past several months, we have received an increased number of inquiries related to H.323 on topics related to tools, deployment, protocol questions, etc. Additionally, others in the videoconferencing community, including equipment vendors and stack vendors, have also reported an increase in activity, including sales, feature requests, and so forth.

With all of this renewed focus on H.323, it was a surprise to receive one message that asked whether there was any work going on related to H.323 since it had been several years since H.323 was updated. Indeed, it has been a few years. Even so, there has definitely been work going on behind the scenes.

In fact, the ITU is planning to approve H.323v7 in November. There are also several other H.323-related documents currently in development scheduled for approval in November. Some may be ready, but some may be delayed. The bottom line, though, is that there is definitely active progress. See the current documents in progress here: https://www.packetizer.com/voip/h323/doc_status.html

Equally important, though, is the fact that there is not as much progress as in previous years on H.323, simply because the standard is fairly mature. There are topics related to Telepresence that the ITU will likely explore, but H.323 is already well-suited for such applications: it is a very stable and mature protocol at this point.

In parallel to the work on H.323, though, there is work on a very new multimedia system that has been slowly moving forward. The new system is called the Advanced Multimedia System (AMS), also known as H.325. H.325 is still in the requirements gathering phase, but the road ahead is fairly clear. H.325 will be an application platform that will enable multimedia communications applications to work together in order to provide a rich communication experience. The objective is to enable users to use any number of devices together seamlessly in a communication session. Equally important, by decomposing the multimedia system into a control element and a set of applications, the system will truly be an open platform upon which application developers will be able to create and deliver new features and functionality without being dependent on any other vendor. It is truly going to be a revolutionary technology that is unparalleled by anything in the industry today.

These are definitely some exciting times. Without a doubt, the ITU continues to lead the charge in delivering powerful multimedia communication systems for the 21st century. And Packetizer is committed to sharing information with the world on the progress of those standards.

Permalink: H.323 and H.325 Moving Forward

Packetizer Deploys XMPP for Instant Messaging

January 4, 2009

With all of the emphasis on VoIP, one of the related technologies that we have not addressed as sufficiently as we should have is instant messaging. During the holidays, Packetizer deployed an open source XMPP server called Openfire. To our delight, it worked flawlessly and significantly better than we had expected. Within minutes, we had the server up and running and communicating with the Google Talk service. Read more about this standard that has become the leader in enterprise instant messaging.

Permalink: Packetizer Deploys XMPP for Instant Messaging

Packetizer Makes Improvements to Daily Payload

October 23, 2008

We are continually working to improve the content offered on Packetizer. Most recently we made significant revisions to the look and feel of Daily Payload. For those who are not familiar with Daily Payload, it is a site where we publish terse summaries and links to news headlines related to VoIP, videoconferencing, mobile communication, WiFi, WiMax, IM, and other technologies related to multimedia communication.

There are two obvious and significant changes that you can immediately see when you visit Daily Payload. The first is that we've changed the color scheme. We now have a light gray background on the sides and a black header across the top. The second and perhaps most substantial change is the logo. We now have a new logo that appears on all pages and the e-mail messages that get sent to subscribers of the Daily Payload news e-mail lists.

One of the features that we added to Daily Payload some time ago is a view of the site designed specifically for mobile devices. If you use a mobile device, you might find that you are redirected to dailypayload.com/mobile. Or, perhaps you will not. We do not have the signatures for every possible mobile device out there, but Windows Mobile, iPhone, and a few other mobile devices are recognized, and users are automatically redirected to the /mobile section.

Another feature added a long time ago is an RSS feed. That probably needs little mention, since it is clear from the volume of traffic to the site that many people have discovered this one. But, in case you are not aware, we do syndicate the postings on Daily Payload via RSS.

A new feature that we have added, but not immediately visible, is the ability to post complete articles on the site through the web browser. We plan to start publishing more original content and would invite people from the public to submit content, as well. If you are interested to write a news article, send it to us for review. We do not object to product promotions, as long as the article also contains useful and interesting information on voice, videoconferencing, or related technologies.

Lastly, feel free to send us feedback on anything you like or don't like. We welcome the input to help improve the growing Packetizer community.

Permalink: Packetizer Makes Improvements to Daily Payload