Smartdefense Not Consistent

[avilT]

On 07th June 2008, we upgraded our Firewall manager from NG FP3 to NGX R65 and deployed the policy on IP390 with NGX R65 software with default smartdefense settings enabled.
Everything was working fine. But on 13th July, suddenly I could see the connection to our web server were getting denied with smart defense signature "ASCII ONLY RESPONSE HEADER"
There was no change done on webserver. Why the smartdefense signature was not active on 14th June when it was initially deployed. Kindly advise.

We do not have Smartdefense subscription.

Thanks

[Thorpuse]

That particular SD protection was on by default in NG, but was revised in NGX. I would *strongly* recommend turning it off, as it will cause you major issues if you transfer large files via HTTP.

[avilT]

This signature blocks from viewing one particular png file on the website whose size is 19 Kilobytes. Why is this behaviour not consistent?
Any other signatures which we should turn off?