Connection Trouble
Shooting
The ISP (internet service provider) is your gateway to the internet though dial up telephone lines which were originally designed for voice communication. As you might guess, this topology adds considerably to the complexity of factors which affect your internet performance. Some of these factors are within your control and can be tweaked. Others are outside the scope of this troubleshooting guide.
Things within your control
Your hardware is a good place to start. What type of modem are you using ? The most frequently occurring problem is incorrect or old modem drivers, which prevent you from getting the most out of your modem. The modem's "inf" file contains the strings which decide how the modem will dial, what type of compression and error control is used, and the connect speed the modem is willing to handshake on. It is surprising that modems from different vendors are able to connect at all.
Then consider your processor speed and memory . Don't expect a 486 with 16 mb of ram to perform nearly as well as a Pentium III/500 with 128mb of ram. The fact is, your processor has as much to do with performance as your modem. If your processor is too busy doing other tasks to process the information stream from your modem, your browsing will be slow. Some modems ( host signal processing=HSP and winmodems ) even require CPU time to perform basic modem functionality and error control. CPUs using the MMX chipset, will also benchmark higher on internet scores.
Worth mentioning is your video card and monitor refresh rate. Older video cards with 1mb of ram and a dinky monitor can cut into the performance edge on a fast machine. This is especially true with multimedia applications and gaming. When in doubt, try using a faster video adapter.
Finally, your disk space. Windows creates a memory swap file called "win386.swp" which is calculated based on free space on your hard drive. As you create work files, windows recalculates the swap file based on what your applications require. The upper limit of your swap file is set by default as the available free space on your machine. The lower limit is usually around 34 mb. You might guess that your browser won't be too happy with a small swap file. You should allocate at least 100mb of free space for the swap file after your browser is installed.
Software
Windows 95/98/NT has two essential components for internet access. Both TCP/IP stack and a dialer through dial up networking, are native to the operating system. Unfortunately, neither of these components is necessarily tweaked for internet and in some cases are outdated (see updates below ). In some cases, using a third party dialer such as trumpet winsock, with the same hardware, is significantly more stable and faster than the windows DUN.
All browsers are not equally rated. The earliest iterations of Internet Explorer are among the poorest of the bunch. IE5 is a substantially better performer. Opera, from operasoftware, is probably the fastest. Benchmarking a browser is an easy task given the huge variations of media types on the internet. In general, you should expect pages with more graphical content or java applets require more time to load with any browser. All the browser benefit from a cache manager such as netsonic or webcelerator. Caching technology, allows your PC to capture details of a web site so the next time you visit, some of the content is served from your hard drive.
Also important is windows registry values for Maximum Transmission Unit (MTU) and receive window (Rwin). The MTU is the maximum packet size that can sent to your modem from your ISP. The receive window is like a buffer. It is the maximum number of packets DUN will accept before sending on the packets. When dial up connection is made, DUN and your ISP have to agree on an appropriate packet size. By default, Windows sets the default MTU at 1500, which is usually too large for modems. Try setting the MTU to 576. Rwin should be a multiple of the MTU.
Finally, it may startle you to know how many programs load when windows starts up. Try "control-alt-del" once, to activate the task manager. More than likely, windows will work fine ( and faster ), if some of these processes did not load on start up. Some internet applications (Yahoo pager, ICQ ) needlessly open the winsock file and unnecessarily tax your CPU and memory. Try removing some applications from the start up folder, or review the configuration options within the program.
Some things outside you control
Teleco line
As if all of this wasn't enough, there are a number of factors related to your telephone line. Noise or static can disrupt your modems signal pattern. Extensions on the line, can "suck" voltage from your modem. Electrical and electronic noise along the entire segment of the telephone conductor from your house to the telephone exchange might be "heard" by your modem. Geographical location can also be important because it affects the length of cable and number of exchanges involved in your call. Let's face it, you will never have a perfect line.
Internet Infrastructure
Once the call reaches the ISP, the routing of your internet request becomes a factor. To make an analogy, even in a fast car, you can only drive as fast as the road will permit. Certain sections of the route may include narrow streets while others are 4 or 10 lane highways. And as might expect, the traffic may thicken at different times of the day. Some sites are busier than others. A site in Japan might be faster from the eastern Caribbean in the middle of the day, than one hosted in eastern united states.
By now, you're thinking, I've got to be a rocket scientist to figure out why I am being frequently disconnected, or why browsing is slow. But this isn't necessarily true. You can usually troubleshoot the problem by looking for a few commonly occurring causes. And we're here to help. If you've gotten this far without feeling heady, chances are you can follow our troubleshooting pages below.
Your modem is a modulation-demodulation device which allows your CPU to acquire packets of information via your phone line. All signaling within your CPU is digital but your phone service is at least partly analog. Hence your modem performs a critical analog-digital conversion (A/D) that make communication possible. To maintain a stable, your modem must synchronize the transfer rates between the analog and digital segments of the connection. Data compression is applied to improve speed.
no values should be specified for TCP/IP in the network applet in the control panel. DNS is disabled and no gateway should be present
Hardware flow control is preferable to software flow control.
FIFO should be enabled in the advanced modem properties under "modems" in the control panel. Also, the receive buffer should never be set as high as the send buffer.
Software compression and IP header compression must be set on in the dialer properties.
A/D's account for performance depreciation in your connection. Noise on your telephone line can also disturb the signal pattern which your modem send and receives. The result, your modem will never attain its rated speed. The process of adjusting connection speed is called "retraining".
You should set your modem and port speed at 38400. If your modem displays a higher connect speed, your modem drivers are actually reporting the speed that the modem and CPU are connected at, rather than the connection to the ISP.
Some modems, often called winmodems, require CPU processing time for error and flow control. You should not use a HSP or HCF modem with an underpowered machine. These modems are designed for Pentium MMX technology, rated at 200Mhz or higher.
You should always use the most updated modem drivers. The modem drivers contain the initialization strings which affect how your modem will dial, what protocols it will use to handshake and the type of compression used.
In some cases, the dial string is country dependent. You should select Japan,South Korea or China in the control panel or in the device manager under modem properties.
Only update your modem firmware as a last resort and only use firmware designed for your specific modem. The best rule of thumb is don't upgrade if it works !
You can often significantly improve your modem's performance by updating DUN or using a third party dialer such as Trumpet Winsock.
Your CPU's power and signal ground are common. Modems can pickup interference from the power ground, which can adversely affect their performance. Make sure your installation is properly grounded (L-N 110-120v, L-G 110-120v, and N-G 1-4v)
Scenario #1. Can't stay online for very long
Possible causes
You live close to a television station or radio tower
fax machine on my internet line
call waiting
bad telephone connectors or slack screws in the jack
ants built a nest in the phone jack
Old type rotary phone on one of my extensions
Too many extensions. Not enough voltage to "power" your modem.
telephone wire cut when stapled to the wall
Table leg on the telephone extension cord
Lightning knocked out your modem
CPU power ground is not effective.
moisture in the external telephone distribution panel
telephone connection not grounded
reversed polarity on your telephone line
power cables installed very close to your telephone wires
UPS, line conditioner with 1ft of your CPU
Modem needs a more robust machine for modulation and error control. Upgrade to at least 32mb Ram with a Pentium 133.
Modem time-out is enabled in the system BIOS
Faulty modem
Incorrect or outdated modem drivers
DUN update needed
Modem speed set too high
Scenario # 2. Can't make a connection at certain times of the day
Possible causes
ISP lines are busy
Pair gain technology being used in your area to provide phone service
Your local exchange is busy
Scenario # 3. Can authenticate but cannot browse or send e-mail
Possible causes
static on your telephone line
Winsock files infected by a virus
TCP/IP stack is corrupted. TCP/IP update needed
"use remote gateway" not specified in the server type settings of the internetworks dialer properties in dial up networking.
TCP/IP in the control panel under "networks", has values stated for DNS and gateway. These should be blank.
Scenario # 4. Can authenticate but browsing is very slow
Possible causes
Using a 14.4 modem
Machine is underpowered. Needs a memory and hard drive upgrade
Too many programs load on start up
Less than 100mb of free space on hard drive. Not space for the windows swap file. Uninstall some programs or remove work files to create space. Or install a new hard disk !
Data overruns. Modem is retraining too often. Hardware flow control is not enabled, FIFO not being used or the receive buffer is set too high
Proxy values specified in your browser
Browser cache is full. Look at the FAQ "how to clear your browser's cache" for more details.
Scenario # 5. Can authenticate, but get disconnected when I open a web page.
Possible Causes
Buffer overflow problem. First make sure "FIFO" is set on then try reducing the size of the receive buffer in the advanced "connection" properties under modems in the control panel and the connection speed under "general"
Winsock is being opened and closed too frequently. Some applications which load on start up ( good examples are ICQ , Media Ring and Netscape Instant messenger ) open and close the winsock files. These two files (wsock32.dll and winsock.dll) in the windows directory, are required by DUN to "interpret" packets of information received by your modem. Try stopping these applications from loading on start up and apply a kernel update. (see "updates" below for more information )
CPU is overtaxed. Too many applications load on start up. Try "control-alt-del" once to launch the windows task list to see how many processes load by default. (systry and explore.exe are essential !). Try uninstalling programs which are not used, and configure your applications not to start with windows. A memory upgrade might help
UART "incompatibility". Universal Asynchronous Receiver Transmitter (UART), is the communication standard between the serial port and your modem's digital signal processor (DSP). The newest standard (16550) means that your serial port has a 16 byte first-in first-out buffer. That means it can receive up to 16 characters before sending an interrupt signal to windows to clear the buffer. If you have an old machine ( with an older standard such as 8550 or 16350 ) and a new modem, the information stream from the modem might exceed what the buffer is capable of receiving or how fast windows can clear the buffer. The result is a comm overrun or CRC error. By default, windows sets the receive buffer at 14 (out of 16 characters).You could try reducing the receive buffer. However, the solution is to replace the UART chip. Internal modems do not generally suffer from this problem because their UART is set within the modem software. Use modem test #2 to verify the UART standard being used for your modem.
Test #1. Noise Test
If you suspect noise on your telephone line, you can perform a basic test. Using an instrument, dial "1". If you hear scratching noises or the recording sounds distant, you could have a noise problem. Try changing the instrument. If you have several extensions, disconnect all of them, and repeat this test at each extension. If you detect noticeable differences, then the problem could be an internal wiring problem or a fault with one of your instruments.
Test #2. Modem Diagnostic
Using the modem applet in the control panel, you can test your modem for certain information. The diagnostic test will test your modems response to certain "AT" or attention commands contained in the modem "inf" or driver file. This test will not check for tone but does reveal certain useful details about the modem.
the communication port, IRQ and I/O address assigned to the modem. Generally, in a machine with two serial ports, the modem is assigned to either COM3 or COM4. The interrupt and base address usually follows the pattern of COM port addressing as below
COM1. interrupt 4, I/O 3f8h
COM2. interrupt 3, I/O 2f8h
COM3. interrupt 3 or 5, I/O 3e8h
COM4. interrupt 4 or 5, I/O 2e8h
In general, modems cannot share address space with any other device in your machine. If this happens, a yellow exclamation is marked against the conflicting device in the device manager (in "system" in the control panel). Some newer modems can use a higher address range and a technique called PCI steering to share address space.
the UART standard. This is the communication standard for the modem port. The most recent is called NS 16550AN. If you have an older machine, and a new modem, there may be UART "incompatibility" which prevents CPU from taking full advantage of the modems capabilities (Scenario # 5 above)
AT response window. Your modem should respond to series of "AT" commands. The response should be "ok" or some other output information. You should find the modem type, rated speed and firmware revision. If this window is blank, your modem is in use, hung up, not properly installed or has a physical defect. If "error" appears as a response, you need newer modem drivers. You may still have basic modem function but some of the modem initialization strings are not supported.
Success with a modem diagnostic does not mean your modem will work with dial up networking. The diagnostic does not check for tone, nor does it force the modem to dial. For a more complete test, try ITSDIAGS or BCM Diagnostics.
Test #3. Basic dial out test
This test forces your modem to dial out independent of any software. First, go to a command prompt. "Start", then "programs" and "msdos prompt". Now type the following
echo ATM1L3X0DT12345 > com <x>
where x= the modem com port.
echo ATH0 > com <x> will hang up your modem. If your modem dials here but fails with dial up networking (DUN), then the problem is a configuration issue with DUN.
Test #4. Online connectivity test
If you can authenticate but cannot browse, the following is a test for connectivity. At the command prompt, type
ping 208.130.114.18 then "enter"
the response should be four lines "replying from" host. If this works, try another command
ping www.opus.co.tt
the response should be the same.
This test can fail or timeout for several reasons.
There is a gateway or DNS values specified in TCP/IP in the network applet in the control panel. No values should appear in TCP/IP and DNS should be disabled
Remote gateway is not enabled in the dialer properties in dial up networking. Open dial up networking, right click on internetworks, choose "server types", then "TCP/IP settings". Now, check remote gateway on
Noise on your telephone line
TCP/IP stack is corrupt. Try shutting down your machine. Or, remove then reinstall TCP/IP under "network" in the control panel. If this happens repeatedly, you may require a TCP/IP update
ISP service is unavailable
If the first entry passes but the second fails, this could be an indication of a Winsock virus or some other issue which has impaired DNS functionality in your operating system. DNS allows your browser to translate words into IP addresses. Apply a complete virus scan ( with the most recent definition ) and then perform a DUN/TCP update. (look for more information below)
Test #5. Throughput test
Using the windows system monitor, you can assess the "stability" of your connection. First, you may have to install system monitor from "add/remove programs", "windows setup" and then enable modem logging under "modem" in the control panel. The modem log is found under the modem properties, "connection", then "advanced". Now, launch the system monitor. Go start, programs, system tools, then system monitor. Say "add item", then either "dial up adapter" or the modems communication port. Choose "bytes received per second" and hit Ok. You should also add "crc error" for your dial up adapter.
Now you're ready. The next time you go online, launch the system monitor. Now, click here to begin a file download. If the bytes/second attain a plateau, with very small variation then, you have a stable connection. However, if CRCs are reported and the bytes/second look like rugged, uneven terrain, then your connection has a throughput problem.
Possible Causes
incorrect or old modem drivers
noise on your phone line forces the modem to retrain frequently
TCP/IP stack requires an update
receive buffer in the advanced modem properties set too high. Open "modem" in the control panel, choose "properties", "connection" then "port settings". Set the receive buffer down a bar. You may have to repeat this with the modem com port in the device manager under "system"
MTU max, Rwin, NDI cache and TTL keys in the registry are suboptimised. Use Netmaster 99, PPPboost, or webcelerator to tweak these values.
Throughput is far more important than connect speed because it reflects how steady the information stream is being received by your modem. During a dial up session, your modem must be able to shift gears when needed. However, when a download is initiated, an uneven stream can cause errors which require the download source to resend a data packet. This slows your file acquisition and in some cases, can also cause packet loss (hence file corruption !). Try Netmedic , Dial up Monitor or Dumeter for more advanced tests of throughput.
"could not open port".
Windows assigns a modem are a communication port. If this error is reported, your modem could be in a hung state. Try turning the modem off the on again (if it is an external modem) or power your machine completely off. The next question is whether your modem's port has been captured by another program or device on start up. Does your fax-answer machine software autostart when windows begins ? If this is the case, you must close your fax software before you initiate a dial up session.If you have more then one modem installed in your machine, the port error will appear if the modem assigned to dial up networking is not the current modem being used ! To check which modem is assigned, open "my computer", then "dial up networking". Now right click on you internetworks dialer, and choose "properties". Look for the assigned modem under "general".
Make sure that your assigned modem port is correct. Open your control panel, then select "modems". Now choose "diagnostic". Choose the communications port assigned to your modem and hit "more information". The response should reveal the port information and the modem response to a series of "AT" commands. If a diagnostic fails, this means that your modem is either not correctly installed or has a physical defect. Check the "system" icon in the control panel for the device manager where the modem port may appear under "ports". If the assigned communication port is absent, you can let windows do a search for it from "add/remove hardware" in the control panel. In some cases,especially winmodems, windows does not show a communication port for your modem and you will have to remove the modem from the device listing and let windows restart. You will probably need the driver files to reinstall your modem.
"error 630: the computer is not receiving a response from the modem. Check that the modem is plugged in, and if necessary, turn off and then back on again"
If powering your machine off resolves this problem, then this error was produced by your windows dialer. The next time it appears, hit "control+alt+del" (at the same time) to activate your task list. Now look for a process called "rnaapp". Select it and hit "end task". Now try dialing again.
This is usually an indication of an errant string in your modem initialization file. Look for a more recent release of your modem drivers to resolve this problem.
"error 633: the modem is not installed or configured for dial up networking. Check your modem configuration. Double click the modem icon in the control panel"
The modem selected for dial up networking is not correct. Click on "my computer", then "dial up networking". If there is more than one internetworks dialer, you should delete all the dialers (including the shortcut on your desktop) , then recreate the internetworks dialer.
To check the dialer properties, right click on the internetworks icon, and choose "properties". The specified modem will appear under "general". Only one modem should appear in the list. If there is a second modem, you should remove the invalid modem from the "modem" icon in the control panel.
"rnaapp. This program has committed an illegal operation and will be shut down" or "rundll error"
This is a windows dial up networking (DUN) error. The solution is a DUN update or rebuilding windows. You may be able to work around this problem with a third party dialer such as Trumpet Winsock.
Dial up adapter
Open your control panel, the "network". Now, select "dial up adapter". Under "bindings", only tcp/ip should be selected. Under "advanced", turn off IPX header compression and record error log on. This will create a PPPlog file when CRCs are generated. Hit "ok" to confirm your changes.
Now look for TCP/IP-dial up adapter. Under the properties, only bind "client for microsoft network" or "windows family logon". Hit "ok" to confirm any changes.
Review your configuration list. If you have more than on dialup adapter listed (including VPN), your can remove these now. When you are done, hit "OK" and windows will prompt you to restart.
Communication Port
If you are using Windows 95, update the file "comm.drv" in the windows system folder with version 4.10.1998. Click here for the update file.
Verify your modem's resources using test#2. Lets suppose your modem is using com1 and interrupt 4. Under the "system.ini" in the windows directory, add the following line under
[386enh]
com1irq4buffer=1024
The effect is to assign some of the system ram to the modem's buffer to be used in periods of peak activity !
MTU and Rwin registry values
Using PPPboost, Netmaster or Webcelerator, you can edit the MTU and Rwin values in the registry. The optimal MTU value varies between 576 and 1500 but varies from one ISP to another. To find your optimal MTU, type the following command
ping -f -l xxx www.networksgy.com
replacing xxx with any value between 548 and 1472. When you have obtained the highest value with the error "packet needs to be fragmented but DF set", add 28 to the number for the optimal MTU.
The Rwin, varies between 3000 and 5000. The optimal Rwin should be a multiple of the MTU. Apply the equation below to work out your optimal Rwin
Rwin= MTU-40 x 3
Minimise the number of programs which load on start up.
Most applications are called to load in one of three locations in windows. Either the window registry, win.ini or the windows startup folder. You can usually stop non-essential programs from loading by editing these locations or adjusting the program directly through its configuration menu.
registry. Look under "HKEY_CURRENT_USER\software\microsoft\windows\currentversion\run and run once"
Win.ini. You can edit the win.ini in the windows folder using the command prompt (Msdos prompt). Type "edit win.ini" and type a "#" in front of lines you want windows to ignore on start up.
Startup folder. Right click on the start bar, then choose "properties". Under "start menu programs", choose "advanced". Now look for the "start up folder". You can selectively remove any programs you wish not to start. Click "ok" to confirm your changes. You can save the deleted shortcuts from the "recycle bin" for future use.
Dial up networking Monitor v2.1
A small but very useful utility for measuring the stability of your dial up connection, and common error such as CRCs and buffer overruns. File size: 180,224 bytes. You may also require a Vbasic file. Click here to get it.
Mdu looks into the registry for values specified on your modem, sound card, browser and tcp/ip. If your registry contains more than one modem reference, this is a great program for removing the additional keys. File Size: 72,240 bytes.
An easy way to examine your modem and ppp log files for potential errors. This is one way to verify the actual modem connect speed, compression and error control standards, and the frequency of CRCs and buffer overruns. File size: 374,784 bytes.
A very simple diagnostic utility that checks your modem, network and browser configuration in one clean interface. If you are experiencing difficulties getting online, checking mail or browsing, this tool can help identify source of the problem. Your mail servers should read "mail.networksgy.com" and you should not have any proxy or DNS values specified. ITSDiag will test your modem initialization, review the modem log, inspect your network services and browser configuration, then allow you to e-mail us these results. File size: 925,696 bytes
If you're experiencing connection problems, Stayconnect can help you analyse the problem. It is dialer utility which keeps your connection alive by randomly requesting web sites. If your modem still times out, this points to a problem with either DUN, your phone line or your modem strings. File size: 899,594 bytes
A small utility which measures the throughput of your connection. Assess what type of impact your adjustments to windows have made. File Size: 407,552 bytes
Net.Medic measures internet performance using performance indicators from your CPU, modem and the Web site being viewed, and then generates reports and suggested fixes for some problems. A great utility. File size: 1,031,680 bytes
Modem Speed Links
These pages will help you rate the effect of your windows updates. Both DUN1.3 and Wisock v2 are recommended for Windows 95. Windows 98 users should apply the VPN update. You may also find that your browsers (and different modem drivers !) perform widely different on each test. As a general rule, you should clear your cache before running these test and close all internet applications (minus your browser) including chat programs and cache managers. The test results are not perfect but these steps will reduce the chance of known errors. (for more on clearing your browser's cache, click here)
Toast.net. An internet service in the US, uses text and graphics test to report the performance of your modem.
Leslie's home page. Four types of test including java to test your internet performance.
Bandwidth Speed test. Bandwidth test page at MSN. Try using Netscape for this test. Try the mouse trap illustration !
When do I need them ?
If you have an earlier version of windows than Windows 98 second edition
If DUN produces rnaapp or rundll errors
If browsing stops suddenly while you're connected, and recycling the power or replacing TCP/IP in the network applet, solves the problem
If you suffer from frequent disconnections but neither your telephone line nor modem configuration show any obvious fault
Get Windows 95 DUN update (appox 2.2 mb)
Get Windows 98 DUN update (approx 318 kb)
Get Winsock v2 for Windows 95 (approx 963 kb)
Get TCP/IP stack update #1 (approx 250 kb)
Get TCP/IP stack update #2 (approx 151 kb)
Get TCP/IP stack update #3 (approx 162 kb)
Get VPN update for DUN1.3 for Windows 95/ 98 (approx 342 kb )
Get Kernel Update for Windows 95a only (approx 329kb)
The updates are executable files which will automatically update files in the windows directory. If you using the first release of Windows 98, you should only update DUN and VPN. Window 95 users should update DUN, winsock and TCP/IP in that order. IE5 also effects some DUN updates when installed. You may need the windows source files to complete the windows 95 DUN update. These updates significantly improve the stability and performance of DUN for the internet. The kernel update is recommended for earlier releases of windows 95 than OSR2 (version 95.4.00.10b) to improve the performance of winsock.
Go IBM help. Telephone tests
Go Microsoft. Modem Troubleshooting
Go Alex Kemps Home page
Go Modemhelp.org
Go Modem fault finder
Go Bugnet.com
Go Help revealed modem page
Go 808hi.com. Great site on modems, vendors and tips.
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