nginx HTTPS and GZIP

Hi,

We're currently implementing nginx into our stack as a proxy which sits above our web servers. We've come across an issue which i'm struggling to understand fully. We haven't enabled gzip in our nginx.conf but we have enabled compression server wide in IIS.

The issue is that all HTTPS requests for our bundled jquery file are timing out or responsing in about 60+ secs.

If I request the file under HTTP it works fine.

If i remove gzip from the Accept-Encoding request header when using HTTPS the file returns fine, unzipped and about a file size of 326kb.

I've also noticed that when requesting the file under HTTP, the file is zipped to 94kb. As we haven't enabled gzip in our nginx.conf i'm suprised this is happening?

We have other zipped javascript files that are returned over HTTPS successfully but the jquery file is the largest?

Are there any specific settings i need to enable for gzip over HTTPS?

Many thanks,
Mike