In customization, open the entity HW Device and create new attribute new_clientcode as nvarchat format= text and maximum length=100.

Display the field in the network tab of the form

Click to select the Web Interface tab and click to open the Form Properties

Select event as OnLoad and click to open the Edit window

Assuming you Nagios URL is: 'http://192.168.10.3/nagios/cgi-bin

Replace the existing JavaScript with:

var url =  'http://192.168.10.3/nagios/cgi-bin/extinfo.cgi?type=1&host=';

url = url +  crmForm.all.new_clientcode.DataValue;

crmForm.all.IFRAME_WebInterface.src = url;

Click OK

Save

Publish

The field new_clientcode is the unique name of the device in Nagios

If the field new_clientcode is not null, the Nagios window will open in the Web Interface tab