Bitzenbytes.com

CompuClues Forum

  User  Password
Friday, September 10, 2010 - 05:05 AM
Search
Main Menu
Who's Online
MEMBERS ONLINE

You are an anonymous user. You can register for free by clicking here
User name
Password
 Remember me
Firefox
Get Firefox 110
Languages
Preferred language:

Comcast 101
Updated: 04.28.2006

Date of document origin: April 19, 2002
Review and update: September 26, 2002
Review and update: February 20, 2003
Review and update: April 26, 2006
  
Frequently Asked Questions, about Comcast, on the CompuClues Forums
  
Q0. What is this document and what does it mean to me? (Important Read)
Q1. Do I have to download Comcast Software to use the Comcast Network?
Q2. Can I get a fixed IP address with a Comcast Account?
Q3. Why does my "speed of access" seem to drop during peak usage hours?
Q4. How fast is the connection to Comcast?
Q5. Can I fax documents through the Comcast network?
Q6. Can I put more than one computer on my Comcast connection to the Internet?
Q7. Do I need a separate access line to use both Internet and TV?
Q8. Can I use VPN with my Comcast Account?
Q9. Can I use video conferencing with my Comcast Account?
Q10. Can I operate a web server on a Comcast Account connection?
Q11. Can I configure and program my own cable modem?
Q12. Should I buy or rent a Cable modem?
Q13. Which is better to use, a cable modem that connects through a NIC, or a cable modem that connects through a USB port?
N.B. Routers used by Comcast customers...
Q14. Does Comcast have a list of cable modems that are supported?
Q15. Does Comcast have a list of cable modems that are not supported or known to have problems?
Q16. Does Comcast care if I use a router or not?
Q17. Does Comcast try to detect that I have a router, and if so why does Comcast do that?
Q18. Are there any exceptions to the answers above? (Either by market, geography, or other division?)
Q19. Will this policy change in the next three years?
Q20. If I use a router (which implies a connecting PC on a LAN) will Comcast help me troubleshoot connectivity problems? (How much or how little? Are there defined limits?)
Q21. Can it be inferred that a modem, that is not on the supported list, cannot be provisioned?
Q22. Does this mean that all are modems on the supported list are DOCSIS compliant?
Q23. Will this list of supported modems be made public, so that anyone can look at it, or must the customer always consult with a service representative prior to making a purchase?
Q24. Almost the same question, but not quite -- How does the customer discover, before making a purchase, whether or not the modem being considered for purchase is supported?
Q25. Who answered these questions and who determined the content of this FAQ document?
Addendum
Q26. I'm only getting one-hour DHCP leases for a couple of days now.  How come?
Q27. What FTP settings work with Cute FTP for uploading to my Comcast Web space?
Q28. How effective is tracert (trace routes) at showing latency?
Q29. Does Comcast have a FAQ section on its website?
Q30. What OS's does Comcast support?
Q31. Does Comcast verify the authenticity of its customers' operating system software?
Q32. Does Comcast block port probing?

 


Q0. What is this document and what does it mean to me?

Before launching into the answer to this question, we wish to report that the FAQ documents available at the Comcast website have greatly improved since the first authoring of this document.  We recommend them as worth looking into.  (More on that in Question 29.)

That said, we haven't yet abandoned the upkeep on this document.  Be aware that Comcast has some incentive to interject a marketing viewpoint along with their helpful information.

The information presented in this document is both paraphrased and quoted directly depending on source.  Specific sources for each individual question are not identified.  The source for the information in this document is many messages left on the CompuClues Forums forums and other public documents.  In general, the questions were asked by forum members and the answers came from Comcast.  If you are concerned about sources for information (and you should be), including this one, please continue reading this section of the FAQ document. 

Where possible, the veracity of the information, given in response to these questions, has been confirmed with Comcast personnel.  In fact, many of these questions have been answered several times in the CompuClues Forums by Forum Member, ComcastOnline.   This has led to the development of this FAQ so that the reposting of answers becomes less burdensome.  It also serves as a collated body of information that may be valuable in itself.  This document is in no way "official" for any organization or business entity.  If you have any question about the information in this document, we suggest that you, both, call Comcast to ask them your questions directly, and to post your question on CompuClues Forums  If any information in this document is discovered to be erroneous, please bring this to our attention in the suggestions forum.  More information about sources is available in the response to Question 25.

No members at CompuClues Forums have been polled on any issue presented in this FAQ.   We would not consider any such poll to be taken from a population that would provide a statistically random sample, and it might not meet other standards of impartiality.  We would point out, also, that random sample inquiries do not always present divergent sides of any issue accurately.  People concerned with one side of an issue tend to like whatever information gathering method will support their view.   CompuClues Forum can make no recommendations about the topics in this document.   Responses that you receive in the CompuClues Forums from members are the views of each individual member and are not the opinions of CompuClues Forums.  More information about sources is available in the response to Question 25.

Top
  
  

Q1. Do I have to download Comcast Software to use the Comcast Network?

No, you do not.  You can use any browser, mail client, FTP client, or other software, that you want to use, as long as that software does not place you in violation of the Terms of Service (TOS.)  Essentially, this means that your software does not offer database, web, or other public services to the internet.

Comcast does recommend the download of their HSI software.  Comcast says that the customer will not be able to take full advantage of the service without it.  This would include the Comcast support utility that is part of the service.

It is clear that some Forum members do not like the software, do not load it, and have no hesitation about advising others to not load it.  We have no way of ascertaining what percentage of the whole that constitutes.  It should be obvious that people who use the software without problem would have little reason to comment on that point in the Forum.  You should weigh these facts when making your own decision. 

In most cases, when this question is asked in the CompuClues Forums, the response by other members is always to not load software.  Members who might say, "go ahead and load the software" could possibly be detered from making that statement or not.  Again, we have no figures on this.  You should make your own decision.  On the other hand, if you were not already inclined to not load the software, you probably wouldn't be asking the question.  So here's the answer: you do not have to download the Comcast software and use it.  Most relatively recent browsers and mail clients should work.   As far as we can tell, members who have not loaded the software, do not feel that they have reduced service.  If you have a question about a specific program that you wish to use instead, one of our members may already be using it and can tell you how it works for them.  If you have loaded the software, one of our members may also have loaded the software and can tell you how it works for them.

Further discussion on this topic is not appropriate to this FAQ

Top
  

Q2. Can I get a fixed IP address with a Comcast Account?

Not with Comcast residential grade service.  On the other hand, the IP address you get will probably be somewhat stable, particularly if you employ a CM (cable modem) and host (a DHCP client) that you never turn off.  For many of us, that DHCP client that never gets turned off is a router with a firewall of some sort.

Top

Q3. Why does my "speed of access" seem to drop during peak usage hours?

Comcast blames bottlenecks on "the Internet."  Considering that many members have seen better performance with other cable network implementations, it's possible that the bottleneck could be Comcast equipment or Comcast's connections to the Internet.  It's clear from the Comcast response that Comcast doesn't want to claim responsibility for this.  CompuClues Forums and its members have no way, at present, of determining what the true root cause of this problem is, nor do we have any suggestions on how it can or should be improved.  (February 20, 2003: This response remains generally the same, but the following comments are notable.  While some members can notice a slow-down during "rush hours", others do not.  One or two people have reported severe problems in the last 5 months, but those seem to be localized.   Judging by lower forum activity for this topic, in general, accessibility during peak usage hours seems to have improved.)

Top

Q4. How fast is the connection to Comcast?

An informal analysis, based on hearsay on these forums, indicates that this varies.   It appears that the reliable readable "speed" is 900 kbps to 1200 kbps for a norm (See update at the bottom of this question for 1500 kbps.)  Anything slower should get the somewhat immediate attention of Comcast following your call to support. 

In various Comcast documents, it seems that Comcast will not commit to a low speed though the low threshold appears to be above ISDN (128 kbps.)  Comcast often promises "better than DSL" (640 kbps), and often advertises "50 times 28.8k" (1440 kbps) which is expressed as "1500k" by some technical representatives.  

Prior to "transition" (Feb 28, 2002), Comcast advertising promised "50 times 56k".  The non-delivery of "50 times 56k" (2800 kbps), post-transition, is a sore point with some CompuClues Forums members.  The key phrase, employed by Comcast, when advertising 1500k, is "up to" meaning that Comcast is only responsible for providing something unspecified "down around."  We've never heard of anybody getting a reading of 1500 kbps on a DOCSIS modem... ...until recently (See update at the bottom of this question.) 

Some members of CompuClues Forums have cable modem equipment that has delivered 3000 kbps to 5000 kbps in the past--the limitation appears to not be the equipment.   Mostly, the limitation to 1500 kbps is enforced by Comcast programming.  The bandwidth available varies with traffic and seems to be the result of Comcast configuration specifications for the equipment.  In general, it appears that traffic bottlenecks, in the network configured, can be responsible for "speed" readings as low as 800 kbps.  This seems to indicate that Comcast has specified (sized) their equipment to be capable of producing no more than the limits that they program.  Readings lower than 800 kbps should be immediately brought to the attention of Comcast, and Comcast should be doing, for you, what is technically possible to improve that.  Your threshold of acceptance may vary.

Update (9/26/2002):  Lately, over the last 2-3 months, a significant number of CompuClues Forums members have been reporting "speed" figures in the 1500 kbps range.  It appears that in some areas Comcast has tweaked it's performance parameters with a resultant improvement. 

Update (2/20/2003): Speed readings have varied in the last 5 months, but some of that, at least, appears to be due to reconfiguration of the network as reported by Comcast.   Though there have been intermittant problems with connections in some areas, our regulars are complaining about speed issues, as an ongoing problem, less.  That doesn't mean necessarily that our members like the current level, but the service does seem to have stabilized somewhat, and we may be tired of ragging on the same old story.   Comcast reports upgrading of their equipment.

Top

Q5. Can I fax documents through the Comcast network?

Comcast does not operate a FAX server.

Top

Q6. Can I put more than one computer on my Comcast connection to the Internet?

Yes.  There are two methods of doing this.

You can employ a router that uses a single IP address to do the work of providing you access to the internet.  See the FAQ section, of a general nature, on Routers, on this page below this section. Use of a router depending on configuration and capability may restrict some usage of the internet (but not much), but meets the requirements of most people needing access for more than one system.  Due to the restriction on bandwidth imposed by Comcast, using more than one system will not increase the bandwidth that you can use.  Understand that Comcast should be able to predict your approximate bandwidth usage within a range--this is the only reasonable way that they can size their equipment and remain profitable.  If you have unusual bandwidth requirements, you should probably be looking at either a professional account or a business account.

Another method is to order additional IP addresses from Comcast.  There are limits and charges involved with this and they could possibly change.  Therefore the quantitative information you read here could change.  At this writing, you can get up to 3 IP addresses at $6.95 per month additional charge per address per month for addresses above the one they give you.   Comcast will charge additional installation fees if a Comcast technician comes to your residence to make this installation.

While there have been no questions about home networking services as offered by Comcast on our forums, we are aware that Comcast was offering installation of home networking solutions on a trial basis in some areas.  As of February, 2003, Comcast was reported to be preparing a full launch of this product, but no details were available.

Top

Q7. Do I need a separate access line to use both Internet and TV?

Usually not.  It is remotely possible, given certain unfortunate technical conditions that you would need either an improved physical connection or another access line to be able to get reasonable reception for both TV and Internet.  If you are having problems, report them to Comcast.

Top

Q8. Can I use VPN with my Comcast Account?

Read through this whole answer.  This is not clear, but the status appears to have changed.  At one time, it seemed that Comcast did not allow VPN usage on a residential account without making an explicit statement about that, but VPN was clearly allowed and advertised for a professional account.  Roughly, you could expect to pay about double for a professional account.  Prices may vary--don't hold us to the estimate and your total bill may depend on what other services you purchase from Comcast.   We quote here the latest statement that we have from Comcast: "Comcast allows customers to utilize VPN software in accordance with our Acceptable Use Policy and other terms of service; however, we do not provide technical support for them. To get support, please contact your software company's system administrator." We interpret this to mean that you can use VPN with your Comcast Account.  If you have any questions about this, we, also, suggest you approach your company's system administrator.

Top

Q9. Can I use video conferencing with my Comcast Account?

Yes.

Top

Q10. Can I operate a web server on a Comcast Account connection?

No. At least not on a residential or professional account. Comcast's Business division can sell you a business account that will allow you to run a server.

Top

Q11. Can I configure and program my own cable modem?

Not by the TOS (terms of service) imposed by Comcast (and every other cable company.)   In general, a DOCSIS compliant modem doesn't allow this.

Top

Q12. Should I buy or rent a Cable modem?

This is pretty much a question about preference, cost, troubleshooting, maintenance, and your level of confidence.  There hasn't been much input on this from the members of CompuClues Forums.  Recent changes in rates, however, may make renting a more viable option than it once was.  People who tend to change jobs and living accomodations frequently have a high incentive to rent.  This answer to this question really depends on the current market.  Clearly, Comcast has buying power and will buy the same modem you can buy at lower cost, and will attempt to make a profit on the margin.  To gain that buying power, they may or may not have to make an agreement to not sell below some determined market average.  You don't know and we don't know either.  Comcast also gains an advantage by being able to standardize a large portion of their support.   Please note that no static document, such as this, can make a recommendation based on any criteria--this industry moves too fast.  You should do the research and get the numbers when acquisition time rolls around for you.

Top

Q13. Which is better to use, a cable modem that connects through a NIC, or a cable modem that connects through a USB port?

The consensus is that a NIC (network interface card) interface is more reliable, less problematic, more portable across most operating systems, more common, and easier to troubleshoot if the interface becomes a problem.  The NIC and cable modem, combined, are also less expensive than cable modems with a USB (Universal Serial Bus) interface. 

Top
  


  
Routers on Comcast Cable WAN Links

OK, there's more questions that will follow, but first, a short setup.  These questions, by the way, were written by Forum Member, Bob, and answered by CompuClues Forums Member, Comcast Online.

Background: Routers are useful for lots of things. Here's just one scenario.

"My" router device is also a switch (hub), a print server, a DHCP server, a DNS forwarder, a NAT device, a firewall device, and a DHCP client. If I only had one PC, I would still want to use the router to connect to the internet because of NAT and the firewall and "my" printer--I don't need to bog down my PC with those chores.

I don't particularly want to rely on a modem that does these things because I can't configure the modem (and other reasons.)

As it stands, I have my home desktop PC and my notebook PC and because of this, I employ most of the features of my router device. I also use this as the gateway between my PC and my WAN link, physically between my PC and my cable modem.

Having established the fact that I want to use a router, and acknowledging that the Comcast TOS lets me do certain things and not others, I have the following questions:

Top

Questions resume:

The following questions were asked in the CompuClues Forums and the respondent was an employee of Comcast.

Q14. Does Comcast have a list of cable modems that are supported?

Yes. We have a comprehensive list that is available to all of our customer support representatives. This list is regularly updated. Modems on the list have met both Cablelabs and Comcast certifications.  As of (at least) February 20, 2003, Comcast has published a list of modems (Manufacturer and model numbers) in it's FAQs documents (FAQDetail_450 -- CompuClues makes no guarantee on how long this link will be stable.)

Top

Q15. Does Comcast have a list of cable modems that are not supported or known to have problems?

There is no specific list of unsupported modems.

Top

Q16. Does Comcast care if I use a router or not?

No. There are no stipulations in the Comcast policy to prevent or discourage the use of routers.

Top

Q17. Does Comcast try to detect that I have a router, and if so why does Comcast do that?

We have no process in place for the detection of routers.

Top

Q18. Are there any exceptions to the answers above? (Either by market, geography, or other division?)

No. This policy is consistent throughout our markets.

Top

Q19. Will this policy change in the next three years?

Unknown.

Top

Q20. If I use a router (which implies a connecting PC on a LAN) will Comcast help me troubleshoot connectivity problems? (How much or how little? Are there defined limits?)

Comcast will support a direct connection to the internet for each computer that you have purchased an IP. Once a direct connection has been verified (defined as connecting the computer directly to the modem), the customer would be responsible for the configuration and troubleshooting of the router

Top

Q21. Can it be inferred that a modem, that is not on the supported list, cannot be provisioned?

Any modem that we add to a customers account must conform to certain database parameters. A modem that is not supported will not be recognized as a valid entry when we try to add it. Because of this, unsupported modems will not be able to be provisioned.

Top

Q22. Does this mean that all are modems on the supported list are DOCSIS compliant?

With the exception of the old Motorola systems, every modem on the list is DOCSIS compliant. (Note: No additional Motorola modems, non-DOCSIS, can be added. Only legacy modems will work on our system).

Top

Q23. Will this list of supported modems be made public, so that anyone can look at it, or must the customer always consult with a service representative prior to making a purchase?

There is a public version of this list published in the FAQs on the Comcast website (See the response to Question 14.)  This list will let you go shopping.  When you settle on something you like, we would still recommend asking a Comcast representative before making a purchase.

Top

Q24. Almost the same question, but not quite -- How does the customer discover, before making a purchase, whether or not the modem being considered for purchase is supported?

Our customer support representatives have access to the most up to date list of certified modems. In addition, we work closely with many of the area retail vendors. The vendors that we partner with will only sell certified modems.

Top

Q25. Who answered these questions and who determined the content of this FAQ document?

The answers have come from three sources and were reviewed by three reviewers. 

The decision about what to include in this FAQ was initially made by simply including the information found in the sources.  No attempt was made to make this a comprehensive description of Comcast resources and services, nor was any attempt made to include information which proports to assess Comcast performance from either the viewpoint of Comcast or the viewpoint of the consumer. As with all such documents, what is included here and what is not included here may have a bearing on the topic.  You are advised to use your own judgement and gather your own facts if you question the content of any part of this document.

The responses to the posted questions come from published public Comcast documents both electronic and hardcopy, from message postings made by CompuClues Forums Members, and from CompuClues Forum Member, ComcastOnline.

In essence, the CompuClues Forums continues the public service that was rendered by the CompuDudes Forum, and was formed by incorporating that forum's message base and members.   CompuClues Forums is fortunate to have retained many of the special relationships forged by the CompuDudes.

On January 25th, 2001, Mitch Bolin, Vice President of Operations, Comcast Online, was a guest of Scott Manning and Peter Cook on the CompuDudes Radio show.  Mitch answered questions from callers.   Lots of callers... ...so many that most didn't make it on the air.  Scott and Peter asked if Mitch would be willing to join the Forum.  Mitch said that he would pass the invitation on to someone with more technical experience than he, to act as a 'Technical Liason'.   That Technical Liason is Forum Member ComcastOnline who joined the Forum a few days later.

ComcastOnline, a Tier 1 Supervisor from Comcast's White Marsh, MD office, volunteers his time on the Forum.  CO, as our Members affectionately call him, has always tried to give us the straight story.  He has, many times, gone above and beyond the call of duty to get our Members' issues resolved answering their questions clearly. We consider ourselves lucky to have him participating in the CompuClues Forums and value this association and friendship highly.  We also think he deserves a raise.

Top
  


Addendum

  
Q26. I'm only getting one-hour DHCP leases for a couple of days now.   How come?

This is normally done just prior to a network upgrade. Setting the lease at 1 hour allows for a quick transistion to a new IP once the upgrade is completed.   The advantage to this is that changes made during the upgrade should be transparent to the user.  There should be no need to reboot or power-cycle any equipment.   If users configure their protocol stack with a static IP address, then when this kind of address change is deployed, it is likely that they will no longer be able to connect.

Top
  

Q27. What FTP settings work with Cute FTP for uploading to my Comcast Web Space?

FTP Host Address.......:  upload.comcast.net
FTP Site User Name....:  your-username
FTP Site Password......:  your-mail-account-password
Port.............................: 21
Login Type..................: Normal

(Click on "Edit" button)

Host type.....................: Auto-detect
PASV..........................: checked

(Click "Advanced" tab)

On left side,
"Use default settings".....: checked
On right side,
Transfer type.................: Auto-detect
And on the bottom,
"Use Global Settings".....: selected.

Top
  

Q28. How effective is tracert (trace routes) at showing latency?

There are two problems with using traceroutes:

1. ICMP packets are considered low-priority packets. A router that is busy handling normal traffic may delay or drop ICMP packets in favor of the higher priority traffic. This will appear as latency on a traceroute when there is no such performance decrease in your normal usage.

2. Traceroutes are asynchronous. An ICMP packet has to travel to the destination and come back again to perform the trace. The path back is not necessarily the path forward. Even when there is a true problem with performance, the traceroute may not accurately pinpoint the problem.

Traceroutes are a great tool to help zero in on a problem, however, it is only one part of the diagnosis.

Top
  

Q29. Does Comcast have a FAQ section on its website?

They do now.  It could be argued that they always did--they are referred to as FAQs now.  The organization of the FAQs is less than clear.  The HTML documents do not appear to be sequentially numbered.  However, there is some useful information there.  For instance, a list of approved modems has been published.  We suggest that seeing what the Comcast FAQs have to say is useful.  It is, after all, the information that Comcast feels is useful to publish.  At least one index to FAQs can be found here. (We really hate making links to websites that change their organization frequently--if you discover that this link is broken, please report it and the new URL.)

Top
  

Q30. What Operating Systems does Comcast support?

PCs:

  • Windows 98, Windows 98 Second Edition, Windows ME
  • Windows NT 4.0 Workstation
  • Windows 2000 Professional
  • Windows XP Home Edition, Windows XP Professional

MACs:

  • MAC OS 9.0,
  • MAC OS 10.2

Not Supported:

  • Windows 95
  • MAC OS 10.0
  • Linux

Note (Further clarification):

Question...These specifications are listed under "System Requirements in the Comcast FAQ.  I have, for instance, used Linux with various browsers and mail clients successfully on a Comcast connection. TCP/IP communication should be OS independent. What implication does "system requirements" have for connectivity or support?

Response...TCP/IP is OS independent. A customer can use any OS that they are able to configure to use with our service. We will simply not provide support in the event that something goes wrong. It is important to distinguish support vs. allow. The same can be said of our support for browsers or email clients. Obviously, almost any browser or email client will work with our service; however, we are only supporting specific programs.

Top
  

Q31. Does Comcast verify the authenticity of its customers' operating software?

(March 20, 2003 - CO) Comcast does not verify the authenticity of its customers' operating system software or whether its customers are authorized users of that software.  However, in order for Comcast to successfully complete some installations of High-Speed Internet service, it is sometimes necessary to use a customer's operating system software disks.  If those disks are unavailable or do not function properly, then Comcast may not be able to complete the customer's installation.

Top
  

Q32. Does Comcast block port probing?

(March 24, 2003 - Comcast FAQ) Port probing is the process in which a hacker attempts to gain access or control of a customer's computer(s).  Comcast cannot prevent a customer from being probed.   Within Comcast's Acceptable Use Policy, it is prohibited for Comcast customers to port probe anyone on the Comcast infrastructure and the Internet.  It is encouraged that customers disable print and file sharing to assist in the security of their system.

Hacking computer systems has been a part of the Internet from its very beginning and will always be part of it.  Many times hackers start automated programs that systematically search through an ISP's infrastructure looking to gain access to computers that are vulnerable.  Once a computer system is compromised, these programs replicate themselves and begin to search the internet again.  Unfortunately, nothing can be done to prevent probes from happening, as it is very difficult to distinguish this type of traffic from other types of network traffic.

Top
  


print Print this | envelope Send this | PDF Download This | Hits: 25110 |
Bugs  |  Tasks  |  Developers