How to fix slow Wi-Fi on the Eir F2000 (Android / IPv6 DNS issue)

Eir’s F2000 router provides IPv4 and IPv6 connectivity, which allows devices to reach websites and web services with native IPv6 connectivity.  While the Eir ISP network handles IPv6 routing, unfortunately its DNS servers seem to stutter with IPv6 DNS lookups, particularly with earlier firmware versions on the F2000.

One workaround is to use an app that tunnels DNS lookups to an IPv4 only DNS server.  While this procedure works, the procedure here aims to let one go online without depending on a third-party app or rooting the phone. 

Unlike IPv4 which uses DHCP for DNS configuration, some clients depend on picking up ICMPv6 Router Advertisements for IPv6 configuration.  This can include IPv6 DNS configuration.  Android currently does not support IPv6 DHCP and relies on Router Advertisements for IPv6 configuration.  In this article, I will show three workarounds.

Note: Eir is now deploying a firmware update (V100R001C59B036) that fixes the IPv6 DNS connectivity for affected devices.  Check the ‘Maintain’ tab in the F2000’s web interface for the firmware version.  If it ends in ‘B036’ or higher, web pages should load quick on Android devices.

If the Wi-Fi / Internet connectivity remains slow on the firmware ending in B036 or newer, try an extended ping test from the command line on a PC, i.e. Press Windows Key + ‘R’, type in “cmd” and click ‘OK’.  In the command prompt window, type in “ping -n 30 google.com”.  If there are multiple “Request timed out” results in a row like the right image, then try “ping -n 30 8.8.8.8”.  If this gives no or very few “Request timed out” results, then there is an IPv6 routing issue.  In this case, follow the “How to turn off IPv6” guide below.

For those that previously followed any of the guides here and would like to undo the changes, see the undo guide below.

• Quick fix for affected devices – Fix Wi-Fi performance on Android by disabling Router Advertisements.
• How to configure Google’s IPv6 DNS addresses – Advanced users looking for full IPv6 connectivity.
• How to turn off IPv6 on the Eir F2000 – Necessary for some Smart DNS services.
• How to undo the changes – For those who would like to undo the changes, such as after receiving firmware ending in ‘B036’ or newer.

For those just looking to fix Wi-Fi performance on affected devices, I recommend carrying out the first guide only.  This should vastly improve Internet connectivity for affected devices such as Android phones on Wi-Fi.

Note: Do not turn off IPv6 in the router’s Internet/WAN settings without first turning off Router Advertisements and IPv6 DHCP.  Otherwise this will potentially lead to problems with every IPv6 capable device on the network.  In this scenario, the router will still assign ‘fe80::1’ as the IPv6 DNS server, as shown on the right.   IPv6 DNS lookups will in turn always fail due to no IPv6 connectivity.  Even without IPv6 Internet connectivity, Android devices will still perform IPv6 DNS lookups before falling back to IPv4 DNS servers.

Quick fix for affected devices

This section shows how to disable Router Advertisements on the Eir F2000.  Android devices currently depend on Router Advertisements for IPv6 configuration.  By turning this setting off, it will force these devices to operate in IPv4 only mode.  This in turn will eliminate the stuttering as they will no longer perform IPv6 DNS lookups.

1. From a web browser, enter http://192.168.1.254/ to bring up the router’s login page.
2. Enter ‘admin’ for the username and the password printed on the back of the F2000, then click ‘Log in’.
3. Go into the ‘Home Network’ tab in the top menu, then into ‘LAN Interfaces’ in the left menu.
4. Open the ‘RA Settings’ section, clear the check box for ‘Enable RA’
   Click the ‘Save’ button and wait a few seconds.
5. On each affected device, put the device into aeroplane mode for a minute or reboot it.  This should clear its existing IPv6 configuration.

Try loading a few webpages on an affected device such as an Android phone.  They should load much quicker now even in IPv4-only mode.

How to configure Google’s IPv6 DNS

For advanced users looking for full IPv6 connectivity, this section shows how to configure the F2000 with Google’s IPv6 DNS.  This can also improve Android connectivity as they are likely to stutter than Eir’s IPv6 DNS servers.

Note / Update 12th October 2017: Unfortunately, in firmware ending in ‘B035’ and earlier, the Eir F2000 does not provide the ability to specify IPv6 DNS addresses without manually specifying an IPv6 prefix for its Router Advertisements configuration.  To make matters worse, Eir periodically changes the IPv6 prefix.  As Eir periodically changes the IPv6 prefix, users who carry out this procedure will need to periodically update the IPv6 prefix.  The telltale sign the prefix changes is when IPv6 connectivity drops and Wi-Fi stutters again on Android devices.  Once the router receives firmware ending in ‘B036’ or newer, follow the ‘Undo guide‘ below, then follow steps #1-#10 here.

I recommend carrying out this guide from a computer with a network cable to the router.  Wi-Fi connectivity may briefly drop out at steps #9, #19 and #26.

1. From a PC web browser, enter http://192.168.1.254/ to bring up the router’s login page.
2. Enter ‘admin’ for the username and the password printed on the back of the F2000, then click ‘Log in’.
3. Go into the ‘Internet’ tab in the top menu, then into ‘Internet Settings’ in the left menu.
4. Look for the connection that says ‘IPv4 status – connected’, then click the ‘Edit’ button in this section.
5. Set the ‘IP protocol version:’ drop-down to ‘IPv4 + IPv6’.
6. Set the ‘IPv6 addressing type:’ drop-down field to ‘DHCP’.
7. If you would like to also use the Google IPv4 DNS, check the box ‘Static DNS’.  Then enter the primary IP address ‘8.8.8.8’ and the secondary IP address ‘8.8.4.4’.
8. If the checkbox ‘IPv6 Static DNS:’ is present, check it.  Then enter ‘2001:4860:4860::8888’ for the IPv6 primary DNS server and ‘2001:4860:4860::8844’ for the IPv6 secondary DNS server.
9. Click the ‘Save’ button and wait a few seconds.
10. If the checkbox ‘IPv6 Static DNS:’ was present in step #8, then skip the rest of this guide.  The steps below are for firmware versions ending in ‘B035’ or earlier.
11. Scroll up and look for the IPv6 status information, which should start with the line ‘IPv6 status: Connected’. If this information is not shown, press ‘F5’ to reload the page.
12. Look for the line ‘IPv6 address prefix list:’ and copy and paste the full address somewhere handy, such as into Notepad.  If you write it down, write it exactly as shown without spaces.
13. Go into the ‘Home Network’ tab in the top menu, then into ‘LAN Interfaces’ in the left menu.
14. Open the ‘IPv6 DHCP Server’ section below and ensure the ‘IPv6 DHCP server:’ field has a check mark.
15. Set the ‘Configuration mode:’ drop-down field to ‘Manual’.
16. Set the ‘Prefix length:’ field to the two digits that were after the ‘/’ in the IPv6 address prefix noted from step #9.  Leave the ‘Prefix’ field blank.
17. In the ‘Primary DNS server address:’ field, enter the Google primary IPv6 DNS: 2001:4860:4860::8888
18. In the ‘Secondary DNS server address:’ field, enter the Google secondary IPv6 DNS: 2001:4860:4860::8844
19. Click the ‘Save’ button and wait a few seconds.
20. Open the ‘RA Settings’ section just above this, ensure the ‘Enable RA:’ field has a check mark.
21. Change the ‘RA mode:’ drop-down field to ‘Manual’.
22. Enter the IPv6 address prefix from step #9 into the ‘Prefix:’ field, then remove the ‘/’ and the last two digits from the end of the prefix.
23. In the ‘Prefix length:’ field, put in the last two digits of the prefix that were after the ‘/’.  See the example below:
24. In the ‘Primary DNS server address:’ field, enter the Google primary IPv6 DNS: 2001:4860:4860::8888
25. In the ‘Secondary DNS server address:’ field, enter the Google secondary IPv6 DNS: 2001:4860:4860::8844
26. Click the ‘Save’ button and wait a few seconds.

At this point, turn off the phone’s Wi-Fi for a few seconds, turn it back on and try loading a few webpages.  They should load much quicker now on Android devices that perform IPv6 DNS lookups.  IPv6 capable network utility apps should now be able to test over IPv6, such as the right Traceroute example.

To check the phone’s IPv6 connectivity , go to http://test-ipv6.com/  If all goes well, webpages should load up quickly and the IPv6 test should complete quickly with a ’10/10′ pass score:

If the Wi-Fi remains slow, such as with older Android devices, first try disabling Router Advertisements (follow the Quick fix guide above).  As Android currently does not support IPv6 DHCP, it will operate in legacy IPv4 mode.

To update the IPv6 prefix (firmware version ending in B035 & earlier): When the IPv6 prefix changes (E.g. IPv6 connectivity drops / Android stutters loading pages), repeat steps #1-#3, #1-#13 and #20-#26.

How to turn off IPv6 on the Eir F2000

If the user prefers to completely turn off IPv6 on the router, perform the following steps.  This process will provide IPv4-only connectivity to all devices on the network and turn off IPv6 router advertisements. This is also useful where the user would like to use a third party IPv4 only DNS such as a Smart DNS.

At present, there are very few web services that do not support IPv4.  However, with the push towards IPv6, this process can potentially lead to problems or performance issues in the future with traffic depending on IPv6 tunnels to reach IPv6 hosts.  With many ISPs still providing IPv4 only connectivity (particularly mobile data), chances are the F2000 will be a museum artefact by the time this happens.

1. From a PC web browser, enter http://192.168.1.254/ to bring up the router’s login page.
2. Enter ‘admin’ for the username and the password printed on the back of the F2000, then click ‘Log in’.
3. Go into the ‘Internet’ tab in the top menu, then into ‘Internet Settings’ in the left menu.
4. Look for the connection that says ‘IPv4 status – Connected’, then click the ‘Edit’ button in this section.
5. Set the ‘IP protocol version:’ drop-down to ‘IPv4’.
6. If you are interested in configuring a third party DNS such as a Smart DNS, tick the ‘Static DNS’.  Here you can enter the DNS IP addresses.
7. Click the ‘Save’ button and wait a few seconds.
8. Go into the ‘Home Network’ tab in the top menu, then into ‘LAN Interfaces’ in the left menu.
9. Open the ‘RA Settings’ section and clear the ‘Enable RA:’ checkbox and click ‘Save’.
10. Open the ‘IPv6 DHCP Server’ section just below this and clear the ‘IPv6 DHCP server:’ checkbox.
11. Click the ‘Save’ button and wait a few seconds.

At this point, I recommend rebooting the F2000 router.  This will force each device to re-establish a connection without picking up any IPv6 configuration from the router.

How to undo the changes

For those that received the firmware ending in ‘B036’ or newer, these steps will undo the ‘Quick fix’ and earlier Google IPv6 DNS configuration.  For those that only ever followed the ‘Quick fix’ guide, perform steps 1-6 only.

1. From a web browser, enter http://192.168.1.254/ to bring up the router’s login page.
2. Enter ‘admin’ for the username and the password printed on the back of the F2000, then click ‘Log in’.
3. Go into the ‘Home Network’ tab in the top menu, then into ‘LAN Interfaces’ in the left menu.
4. Open the ‘RA Settings’ section, tick the box for ‘Enable RA’
5. Set the ‘RA mode:’ drop-down to ‘Automatic’.
6. Click the ‘Save’ button and wait a few seconds.
7. Open the ‘IPv6 DHCP server’ section.
8. Ensure the ‘IPv6 DHCP server:’ field has a check mark.
9. Set the ‘Configuration mode:’ drop-down to ‘Auto-configure subnet’
10. Click the ‘Save’ button and wait a few seconds.
11. Go into ‘Internet’ menu at the top, then into ‘Internet Settings’ in the left menu.
12. Look for the connection that says ‘IPv4 status – connected’, then click the ‘Edit’ button in this section.
13. Set the ‘IP protocol version:’ field to ‘IPv4 + IPv6’.
14. Set the ‘IPv6 addressing type:’ field to ‘DHCP’
15. Click the ‘Save’ button and wait 30 seconds.
16. On each affected device, put the device into aeroplane mode for a minute or reboot it.  This should clear its existing IPv6 configuration.

Try checking the Wi-Fi connectivity on any device that was affected, such as an Android device.  It can take a minute for the connection to stabilise, after which the Wi-Fi performance should be quick.

Article revisions:

• 29th September 2017 – Revised the guide after discovering that Eir periodically changes the user’s IPv6 prefix.
• 1st October 2017 – Added a quick fix guide for those just interested in fixing Wi-Fi performance on Android devices.
• 4th October 2017 – Added note about turning off IPv6 in the Internet/WAN settings.  Added resulting Android IPv6 configuration screenshots.
• 12th October 2017 – Added an undo guide now that Eir released a firmware update (ending in ‘B036’) that fixes the IPv6 DNS connectivity.
• 1st November 2017 – Added a quick test to check if there is an IPv6 connectivity issue to rule out the DNS.