How to query using a large buffer?

[PaulBrown]

I am writing a web page that gets a point and a buffer and then queries for all the zip codes within the buffer.  I works fine for anything up to a 15 mile radius, but when I try a 20 mile radius I get an instant error 500 response when I try to get the zip codes.  I am guessing the 500 is coming from the proxy and maybe the parameters are bigger than the IIS server is allowing to be passed into an .ashx page?  Does anyone know how to fix this issue?

[ThaoLe]

Have you tried breaking up the query into multiple queries?

Also, do you know where in the proxy page the error is coming from?

[StephenLead]

when I try a 20 mile radius I get an instant error 500 response

Can you provide the code that you're running?

What is the URL which is being called? For example, a query running on a sample ArcGIS service uses:

http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/5/...

Steve