Correct half bridge setup?

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plo009

107 posts

Master Geek

#105240 29-Jun-2012 22:40

Hi guys

I'm unsure if i have done my half bridge setup correctly. I did my setup following an old guide from http://www.ben.geek.nz/2006/11/adsl-routing-solution-in-detail/

My current setup is the tp link 8840 and 1043nd router running gargoyle custom firmware.

Unfortunately due to my limited knowledge and the guide using different modem, router and custom firmware for the router, it was difficult for me to make sure that i have done everything correctly.

The only change i recall doing to the modem was:
Updating the firmware
Changing the ip range of the modem to 10.0.0.1
Enabling ip extension

I've read online that if set up properly in half bridge mode, you should not be able to access the web interface of the modem. Strangely I am occasionally able to access it from 10.0.0.1 wirelessly for short period until it randomly disconnects me telling me the webpage is not available.

Some posts on the forum also suggests that the DHCP to be disabled for the 8840 for half bridge, but I could not locate anything related to the DHCP on the modem for some reason...... The user guide I found from tp link shows a slightly different interface to mine.

Cheers

DrStrangelove

368 posts

Ultimate Geek

#648519 29-Jun-2012 23:15

Sorry to ask a dumb question, but you do have a TD-8840 and not a TD-8840T

The 'T' model does not do a half bridge.

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plo009

107 posts

Master Geek

#648521 29-Jun-2012 23:25

Hi, I'm positive i'm using the 8840 not 8840T, went through alot of trouble to get my hands on them as well since they were discontinued

sidefx

3700 posts

Uber Geek

Trusted

#648527 29-Jun-2012 23:40

I haven't tried the 8840, but I tried another TP-Link (TD-W8960N) when my first RTA1320 was on the fritz and had a fair bit of trouble with it.

One thing I found is that if you change the IP address to something else, it's best to change the DHCP server to match, save that, then turn off DHCP, then turn on the PPP extension. Sounds weird but it seemed more consistent. Also had some odd issues with latency when using the TP-Link in half bridge... I've now got another RTA1320 and it's working much better.

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plo009

107 posts

Master Geek

#648642 30-Jun-2012 13:56

After a bit of playing around, i think the DHCP enable/disable option disappears automatically once you tick the ip extension option. The strange thing is the web interface seems to crash quite easily and doesn't function until the modem is restarted yet the internet connection still works fine while i can not access the web interface....

chevrolux

4962 posts

Uber Geek
Inactive user

#648671 30-Jun-2012 15:12

Once you tick IP Extension it disables all NAT, DHCP, QoS and firewall features. Just put the modem in a different subnet as your LAN and you are good to go. Accessing the web interface of the modem from within your LAN is entirely up to the firewall rules.
You can check to see if the IP Extension is working by plugging your computer directly in to the modem. Do an IPCONFIG and your computer should have your public IP address.

plo009

107 posts

Master Geek

#648786 30-Jun-2012 21:04

chevrolux: Once you tick IP Extension it disables all NAT, DHCP, QoS and firewall features. Just put the modem in a different subnet as your LAN and you are good to go. Accessing the web interface of the modem from within your LAN is entirely up to the firewall rules.
You can check to see if the IP Extension is working by plugging your computer directly in to the modem. Do an IPCONFIG and your computer should have your public IP address.

Is that supposed to be something like 111.69.197.XXX?

djtOtago

1127 posts

Uber Geek

#648832 30-Jun-2012 23:37

Is that supposed to be something like 111.69.197.XXX?

Yes.

I assume you are with snap with an ip address like that :)

plo009

107 posts

Master Geek

#648849 1-Jul-2012 00:38

I assume you are with snap with an ip address like that :)

Yip, i'm using snap. So i did setup the half bridge correctly and the reason i cant access the web interface for the modem is probably because it crashed or locked me out?

webwat

2036 posts

Uber Geek

Trusted

#649117 1-Jul-2012 16:10

plo009:
I assume you are with snap with an ip address like that :)

Yip, i'm using snap. So i did setup the half bridge correctly and the reason i cant access the web interface for the modem is probably because it crashed or locked me out?

Its probably because your router remembered that 10.0.0.1 is supposed to be a non-routable address and stopped routing it. You could also try full bridge setup using PPPoA-bridge instead of half-bridge mode, so that you have to setup PPPoE in your router. That would ensure the router always knows whether its connected or not, and you can see username etc despite having no modem interface.

Time to find a new industry!

plo009

107 posts

Master Geek

#649215 1-Jul-2012 20:20

You could also try full bridge setup using PPPoA-bridge instead of half-bridge mode, so that you have to setup PPPoE in your router. That would ensure the router always knows whether its connected or not, and you can see username etc despite having no modem interface.

I thought i can only do half-bridge setup with PPPoA and my equipment? I use a tp-link 8840 modem and 1043nd router running gargoyle. I did hear that the draytek vigor 120 can to pppoa to pppoe though which than allows full bridge.

sbiddle

30853 posts

Uber Geek

Retired Mod

Trusted

Biddle Corp

Lifetime subscriber

#649222 1-Jul-2012 20:33

My recommendation is always a Draytek DV120, this does transparent PPPoA to PPPoE conversion and avoids all the pitfalls of using the many cheap and nasty modems.

The other (but more expensive option) is to use a modem such as a Zyxel in bridge mode which will allow you to set VLAN10 on the WAN and use native PPPoE on ADSL2+ however this will only work if you are on an EUBA connection and your ISP supports this scenario as PPPoA and PPPoE are presented on different VLAN tags to the ISP.

plo009

107 posts

Master Geek

#649227 1-Jul-2012 20:44

sbiddle: My recommendation is always a Draytek DV120, this does transparent PPPoA to PPPoE conversion and avoids all the pitfalls of using the many cheap and nasty modems.

The other (but more expensive option) is to use a modem such as a Zyxel in bridge mode which will allow you to set VLAN10 on the WAN and use native PPPoE on ADSL2+ however this will only work if you are on an EUBA connection and your ISP supports this scenario as PPPoA and PPPoE are presented on different VLAN tags to the ISP.

What advantage does a full bridge setup brings me over half bridge? Considering i just spent $40 earlier to get a 8840 a month ago, feels a bit wasteful to purchase a dv120 now and have no use of it.