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Do you provide static IP addresses on your ADSL service?

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Yes, we provide fixed IP addresses that are dynamically allocated but consistently served (so you get the same IP address every time your router logs in). This is the most suitable option for businesses who need to run their own mail servers or set up VPNs between sites.

What is the ADSL Max speed?

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The MAX product provides download data rates of up to 8Mb/s with Maximum upload data rates from 256 kb/s (standard ADSL) up to 448 kb/s (Max) and 832 kb/s (Premium Max).


IPstream Max is a ‘best efforts’ product, and thus no guarantee is given that increased data throughput will be experienced over that of the IPstream Office and Pro products. Where a customer upgrades from a fixed rate product to Max the speed their line achieves might be lower than they previously had.


The actual speed a line achieves is dependant upon:


  • Line length
  • Line quality
  • Electrical Interference


It is quite possible for two geographically close to have different line speeds.
IP throughout is dependant upon other factors such as server rate limiting. User will NOT be able to download files from the Internet at anywhere near 8Mbps.


Best speed
The best possible speed is determined by a service called Digital Line Management. This uses a variety of techniques to find the Maximum Stable Rate that a line can support.


(Minimum) 10 day Training period
To achieve the best possible speed when a line is first connected a new line undergoes a minimum 10 day training period to determine the Maximum Stable Rate. During this period line speed will vary and some disconnections will be experienced. This is correct behaviour and we are unable to log faults during this 10 day training period.


Digital Line Management contnually monitors line performance and adjusts speeds if necessary.

Common ADSL router settings?

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Setting – Value
VPI – 0
VCI – 38
Carrier Modulation – G.DMT *(see note below)
Multiplexing – VC based
Encapsulation – PPPoA (NOT PPPoE)
Authentication – CHAP
WAN IP address – Dynamic
DNS server –
DNS server –


* NOTE: for ADSL2+ services Carrier Modulation should be set to ITU G.992.5

ADSL troubleshooting guide for Speedtouch router

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Download attached PDF for a useful troubleshooting guide

I’m having problems accessing/downloading from certain websites/ FTP sites. I’m having problems with VPN/ transferring data over VPN?

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MTU settings can cause problems with VPNs and accessing certain websites.


By default Ethernet uses an MTU size of 1500 bytes so that is often what the MTU size will be set to as default on a PC network card. Spitfire ADSL supports an MTU of 1500. However it may be that not all the devices between you and the server (routers/firewalls) you are accessing also support a size of 1500 bytes. In addition VPN and GRE tunnels cause problems because the tunnels reduce the effective MTU of a connection. So a VPN tunnel over an ADSL line will certainly have an MTU of less than 1500 bytes.


Why not just set the size very low? – the “Internet standard” for MTU is 576 but that is often too low. A low MTU means the efficiency of the connection is reduced because every packet requires headers which are an overhead (don’t carry user data).


Finding the optimum size for your MTU will often resolve issues and give better overall performance.

How to determine optimum MTU size

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Determining the optimum MTU size from a Windows Machine
From a Command Prompt type:


Ping –f –l 1500


-f means set the Do not Fragment bit in the TCP header
-l means fix the size of the packet in bytes
1500 sets the packet size to 1500


The destination host should be the one you are having trouble reaching, or a server on the other side of the VPN is you are having VPN problems.
Z:\>ping -f -l 1500


Pinging [] with 1500 bytes of data:


Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.


Ping statistics for
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),


Reduce the size of the packets sent until a value is reached where packets are correctly returned:


Z:\>ping -f -l 1272


Pinging [] with 1272 bytes of data:


Reply from bytes=1272 time=103ms TTL=124
Reply from bytes=1272 time=103ms TTL=124
Reply from bytes=1272 time=103ms TTL=124
Reply from bytes=1272 time=103ms TTL=124


Ping statistics for
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 103ms, Maximum = 103ms, Average = 103ms


Here a packet size of 1272 works OK. To get the MTU value we need to add 28 bytes for the TCP header so we should set the MTU to be 1272 + 28 = 1300 bytes.

Why do downloads start fast then slow down?

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As soon as you click on download file the download starts, even though you have yet to type in a filename or find a location to save the file. When you eventually click OK a fair amount of data will already have been downloaded. When the download speed is calculated initially it appears that the data rate is higher than it actually is because of the data that has already downloaded waiting for you to click OK.

How do I set the MTU on a Windows PC?

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On a Windows machine the safest way to set the MTU to a new value is download a tool called “Dr. TCP” which will allow you to set a new value of MTU for the network adaptor card. Other Registry editing tools are available. You will need to reboot your machine for the new settings to take effect.

What to do when the Speedtouch ADSL router drops the connection to the Internet?

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Usually, by turning off and on, i.e. powercycle, the Speedtouch from the switch at the back will resume Internet connectivity.


However, sometimes routers develop stale sessions due to prolonged uptime of the device itself over a number of days or weeks that a simple powercycle will not fix.


In these cases, it is advisable to perform a complete restart of the router. There are two possible procedures to follow:


Procedure A:


  1. unplug both the Power and ADSL cables from the back of the Speedtouch.
  2. wait for 10 seconds
  3. next, reconnect the Power cable back in and wait for the Speedtouch to fully initialise. The Power LED will first become red and finally go solid green.
  4. second, reconnect the ADSL cable back in and wait for the DSL LED to go solid green. Finally, the Speedtouch should connect by showing the Internet LED in green.


Procedure B:


If the first attempt does not resolve the problem, a second restart can be performed by following procedure A but with a wait of 20 minutes at step 2 instead.

How can I perform a speed test on my line?

Show Answer

Please use

For an accurate result the test should be done with nothing else connected to the service.

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