Showing results for 
Search instead for 
Did you mean: 

Welcome to the Cisco Small Business Community

Have a question? Click on a topic board below to get started in the community.

Joachim Winkler

AP541N keine Antwort vom DHCP-Server bei iPhone

Hi Community,

we have an AP541N as WLAN access point. Through it all WLAN clients are getting their IP-address from our

DHCP server (SBS2003). Since a few days all iPhones don't get an IP-adress, but portable PCs and desktop PCs

do get an IP-address.

With wireshark I can see, the iPhones are repeating their DHCP-discover but our DHCP-server doesn't answer with

a DHCP-offer.

I've already updated the AP541N to the latest firmware AP541N-K9-2.0(4).

The AP541N shows on its status page : all clients (iPhones, LapTops) are authenticated.

There is only one DHCP-server in our network.

All devices have reserved IP-addresses acording to their MAC adresses.

If I give an iPhone a fixed IP-address it works in our network.

What could be the reason for this effect, no IP-addresses for iPhones ?



Hallo Community,

wir haben bei uns eine AP541N als WLAN Zugangspunkt. Über ihn erhalten alle WLAN Clients ihre IP-Adresse von

unserem DHCP-Server (einem SBS2003). Seit einiger Zeit erhalten alle iPhones keine IP-Adresse mehr, wohl aber

Laptops oder Desktop-PCs.

Mit Wireshark kann ich sehen, dass die iPhones ihren DHCP-Discover ständig wiederholen aber keinen DHCP Offer

vom Server erhalten.

Den AP541N habe ich bereits auf die neueste Software upgedated AP541N-K9-2.0(4).

Der AP541N zeigt für alle iPhones an, dass sie im WLAN authentifiziert sind

Es gibt nur einen DHCP-Server im Netzwerk.

Er vergibt für alle Geräte reservierte IP-Adressen auf Grund derer MAC Adressen.

Wenn ich einem iPhone eine feste IP-Adresse gebe funktioniert der Netzwerkverkehr.

Woran könnte es liegen, dass ausgerechnet nur die iPhones keine Antwort vom DHCP-Server bekommen ?

Herzliche Grüße


Rising star

Hi Joachim, thank you for using our forum, my name is Johnnatan I am part of the Small business Support community. I apologize for this inconvenience you are having, I advise you to use less change your security parameters, sometimes these devices don´t support strong protocols, however if this doesn´t resolve your issue, can you please reach out to our Small Business Support Center and open a Service Request to address this issue? One of our Engineers may be able to work with you and diagnose the root cause. You can find the appropriate contact information for SBSC in the below link.

I hope you find this answer useful

“Please rate useful posts so other users can benefit from it”

Johnnatan Rodriguez Miranda.
Cisco Network Support Engineer.

“Please rate useful posts so other users can benefit from it” Greetings, Johnnatan Rodriguez Miranda. Cisco Network Support Engineer.

Hi Jonathan, thanks for your answer.

I've tried the online chat support for partners (Germany) now several times.

It seems nobody is there.

Do you have any other idea where I can get help ?



Hello Mr. Winkler,

Please call us on one of the numbers listed below:

We would be glad to assist you!