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Trusted Contributor
ttl_expired
Posts: 429
Registered: ‎11-11-2008
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Accepted Solution

AP in Different Network

Hi All,

 

    I have the following issue.  I have an MXR-8 sitting at my head office and an MP-522 at a remote location.  The two sites are connected via a VPN tunnel.

 

I have configured DHCP at the remote site to have option 43 with an IP address of the MXR-8.  The AP does not seem to be even trying to talk back to the controller (I am looking at SSG traffic logs and dont see the AP talking across the tunnel).  I have tried 2 different DHCP server and still no luck.

 

I have a wireshark capture on a laptop at the remote site and I can see the AP goes through a TAPA broadbast cycle every now and again to try and find the controller.

 

I am at a loss as to what to try next.  The document says use DHCP option 43 but is this right?

 

EDIT****

 

I just tried the last ditch method of setting up a DNS name with TRPZ and this works.  This leads me to believe something is not right with DHCP option 43

 

Thanks for any help



Trusted Expert
Trusted Expert
jtb
Posts: 308
Registered: ‎08-26-2009

Re: AP in Different Network

Hi Magraw,

 

not long ago I plugged MP-522 to my home network (NAT/ADSL ->Internet) and it connected to MX-800R/WLC800 (software 7.3.4.4)  with public IP address.

 

I have successfully tested both methods of controller discovery:

 

  1. DHCP with options 43
  2. DNS name for controller  - TRPZ.domain.xyz  (with name 'domain.xyz' served by DHCP)

For (1) I used small DHCP deamon on my PC (tftpd32.exe), since my ADSL router has no way to configure DHCP options.

 

The tftpd32 specific config file have the lines:

 

AddOptionNumber1=43

AddOptionValue1=ip:X.Y.W.Z      

 

The format for the option 43 is string "ip:X.Y.W.Z", where X.Y.W.Z is the MX address.

I guess your problems are related to format of the DHCP options 43 - it must a a string "ip:X.Y.W.Z"

 

Just for the record: the setup was working fine, had some problems with packets close the MTU size. My math says the path MTU should be enough for the MX-MP requirements and, AFAIR, my debugging showed traffic from MX to MP was lost  - could be a problem with my ADSL router.  MP -> MX direction was fine.

 

Test the DHCP options and update us with the outcome,

jtb

 

Trusted Contributor
ttl_expired
Posts: 429
Registered: ‎11-11-2008
0

Re: AP in Different Network

jtb your a lifesaver.  That string works great.  I tried it on SSG and Windows and both take it.  Strange that the document I was using did no mention having the ip:x.x.x.x as the string.

 

Thanks again

Trusted Expert
Automate
Posts: 784
Registered: ‎11-01-2007
0

Re: AP in Different Network

Welcome to the WLAN board!

 

@Magraw - which doc? If you can provide the URL/title we can work on getting it amended.

 

regards

 

-Keith

Trusted Contributor
ttl_expired
Posts: 429
Registered: ‎11-11-2008
0

Re: AP in Different Network

It was a Smart Focus Course on Centrally Managed Deployments.  I have no URL as I got it from my SE.

 

I would not say it was wrong so much as it just did not specify the details.

 

excerp bellow

 

1 DHCP Option 43
❍ Define an Option 43 list of IP addresses (or host names) on the DHCP server scope
used for assigning IP configurations to APs.
❍ The AP will attempt TAPA unicast connections to each of the IP addresses
specified.
2 L2 Subnet Broadcast
❍ The AP broadcasts a TAPA ‘find MX’ message over UDP on port 5000.
❍ Any MX that hears the broadcast will respond.
❍ MXs with Bias set to ‘High’ will respond immediately.
❍ MXs without a configuration for the AP will respond after a longer delay to
re-direct the AP to a Mobility Domain MX with a valid configuration for that AP (to
give a ‘High’ or ‘Low’ Bias MX the opportunity to take control of the AP).
3 DNS Lookup
❍ Used only if the Option 43 and L2 Subnet Broadcast processes fail to find a MX.
❍ AP looks up the hosts ‘trpz’ and ‘wlan-switch’.

 

Trusted Expert
Trusted Expert
jtb
Posts: 308
Registered: ‎08-26-2009
0

Re: AP in Different Network

hi,

 

the ex-Trapze technical documentation is now available at Juniper site:

 

http://www.juniper.net/techpubs/en_US/release-independent/wireless/information-products/pathway-page...

 

Regarding your problem,  'Distributed MPs and DHCP Option 43' chapter (page 183) of 'Mobility System Software Configuration Guide' says:


[...]To use DHCP option 43, configure the option to contain a comma-separated list of MX IP addresses or hostnames, in the following format:

 

ip:ip-addr1,ip-addr2,...

or

host:hostname1,hostname2,...

 

There is more info worth  reading.  

 

The major problem with the documentation is that after conversion to Juniper style, bookmarks (table of contents) in the PDF file is gone.  It's really hard to find correct chapter if you don't know the book.

 

Juniper please fix it !

 

jtb 

Regular Visitor
james.akpan@layer3.cc
Posts: 4
Registered: ‎06-30-2011
0

Re: AP in Different Network

Hello Experts,

 

I am trying to configure DHCP option 43 and each time i try, i get this error message:

 

{master:1}[edit system services dhcp]
admin@NET-AS-EX4200_24P-ADM-01# show
router {
10.10.10.1;
}
pool 10.10.10.0/24 {
address-range low 10.10.10.5 high 10.10.10.20;
option 43 string ip:10.10.90.1;
}
pool 10.10.19.0/24 {
address-range low 10.10.19.3 high 10.10.19.50;
}

{master:1}[edit system services dhcp]
admin@NET-AS-EX4200_24P-ADM-01# commit synchronize
[edit system services dhcp pool 10.10.10.0/24 option 43 string]
'string ip:10.10.90.1'
Option 43 must be defined as an array type
error: configuration check-out failed

 

Please what am i doing wrong???

 

Thanks!

 

Regards,

James.

Trusted Contributor
kronicklez
Posts: 436
Registered: ‎08-10-2010
0

Re: AP in Different Network

Hi All,

 

 

Is there any solution for this problem? Thanks

Trusted Expert
Trusted Expert
jtb
Posts: 308
Registered: ‎08-26-2009
0

Re: AP in Different Network

Trusted Contributor
kronicklez
Posts: 436
Registered: ‎08-10-2010
0

Re: AP in Different Network

Hi Jtb,

 

 

Thanks for the url. So u mean must use byte stream to have DHCP option 43 right? One more thing is this DHCP Server (windows platform) support this option? Thanks and appreciate your feedback.

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