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I am trying to use my router as an extension to my existing wlan. The connection seems to work fine, because I can ping the internet router from the tp-link. Also the status page of the tp-link shows an ok status.

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If I am connected to the internet router, I can access the admin page of the tp-link. But when I am connected to the tp-link, I just can access this host and nothing else. The routing table of the tp-link looks like this:

enter image description here

The ip address of my internet router is 192.168.1.1, the address of tp-link is 192.168.1.99.

I need to have DHCP on tp-link on, otherwise I don't get an ip address.

Any ideas what is wrong with this setup?

Hennes
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Dominik
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  • Please explain how you set up the connection. Also, like harrymc wrote, you wouldn’t need DHCP on the TP-Link router if it were working correctly. – Daniel B Oct 23 '16 at 08:38
  • The connection is done by Wifi (WDS). I can ping the internet router from the extending router, and I also the other way round. What does not seem to work is the transport of the packets via the extending router. – Dominik Oct 23 '16 at 12:10
  • When connected to the internet router, I can reach the web-interface of the extending router with my laptop. But when I am connected to the extending router, I cannot reach the internet router (neither by ping nor by http). – Dominik Oct 23 '16 at 12:11
  • So I guess WDS isn't working after all. WDS is almost always proprietary these days. What's the upstream router's make and model? – Daniel B Oct 23 '16 at 13:35
  • It's a Huawei E5170s-22. I am afraid you are right. But it's strange that it works in one direction (laptop connected to internet router can access extension router) but not the other way (laptop connected to extension router can access internet router). Nevertheless thank you for your help. – Dominik Oct 23 '16 at 17:23
  • Finally got an answer from tech support from tp-link: they do not support WDS and also do not recommend to use it, because it is unsafe. – Dominik Oct 25 '16 at 20:23

2 Answers2

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WDS is not standardized. Additionally, it was originally designed for WPA security, not WPA2. That means it’s not suitable for modern WiFi networks. Some manufacturers create proprietary derivatives of WDS that can be used with WPA2. Naturally, these implementations are not compatible with other manufacturers. This is also why it’s not working here.

The connection seems to work fine, because I can ping the internet router from the tp-link.

[...]

But it's strange that it works in one direction (laptop connected to internet router can access extension router) [...]

Neither of these requires WDS. If the TP-Link router pings the Huawei router, it acts as a regular WiFi client. The opposite direction is of course the same.

The OpenWrt wiki has a great explanation on why WDS is great for bridged clients or repeating. The gist: IEEE 802.11 is designed with the assumption that a wireless client (station) has nothing “behind it”. There is no concept of packets coming from or going to a station that don’t originate from/are destined for the station itself. This is unlike Ethernet. WDS (4-address mode, really) introduces a method of making it work like Ethernet.

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Daniel B
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  • Thanks for the detailled explanation. Just to clarify, in this case, the oposite direction is not quite the same because: – Dominik Oct 28 '16 at 06:21
  • this works: laptop -> internet router -> ext. router and this not: laptop -> ext. router -> internet router – Dominik Oct 28 '16 at 06:22
  • It's is the same though: you're accessing the TP-Link itself, not what's behind it. – Daniel B Oct 28 '16 at 06:38
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If the Internet router does DHCP, you need to turn this function off in the tp-link and also give it an unused static IP address that cannot conflict with other devices. You could reduce the range of IP addresses on the Internet router to ensure no conflicts.

The tp-link needs to be connected to the Internet router using an Ethernet cable as Lan-to-LAN. See this answer of mine for how the cabling should go.

For a detailed description of what you need to do, see the article
How To Convert a Wireless Router into an Access Point.

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harrymc
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  • I would like to connect the two routers by WDS, not by Ethernet. – Dominik Oct 23 '16 at 12:07
  • See the article [How to Configure WDS Bridging on TP-Link Dual Band Routers](http://www.tp-link.us/faq-440.html). I remark that there might be difficulties to make it work between routers of different manufacturers. – harrymc Oct 23 '16 at 16:20
  • I found this article as well, but I didn't succeed to get it work. I am afraid it won't work with WDS because of incompatibilities. Thank you for your hep. – Dominik Oct 23 '16 at 17:25