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Rank: Newbie
Groups: Member
Joined: 2/1/2008
Posts: 5
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I am using the EO menu in my master page, and all my site's pages use this master. I also have a generic error handling routine which sends all exceptions and the stack trace to me. About twice a week on average, I get emailed a System.NullReferenceException that involved the EO components. It tends to come in groups - if I get one, then I will get five or more in succession.
I have never seen this error in development, and never in production when I am browsing the site. Please let me know if you can tell me what causes this and what the solution is. Also, please let me know if you need more information. Thanks.
Stack Trace: at EO.Web.Internal.e1.a(HtmlTextWriter A_0)
at EO.Web.BaseNavigator.a(HtmlTextWriter A_0)
at EO.Web.WebControlBase.b(HtmlTextWriter A_0)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at ASP.masterpage_master.__Renderform1(HtmlTextWriter __w, Control parameterContainer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Control.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Page.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
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Rank: Administration
Groups: Administration
Joined: 5/27/2007
Posts: 24,095
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Hi Michael,
Check your web server's log and try to find out the user agent when you get this error. This occurs when an user agent pretents to be FireFox but does not set the UserAgent string correctly, which means the request comes from a web spider (FireFox itself would have the correct UserAgent string). We have yet to find out what spider this is, but we know it's not from the big search engines like Google, Yahoo or MS (please let us know when you find out. :P), so it's pretty safe to ignore it.
Thanks
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Rank: Newbie
Groups: Member
Joined: 2/1/2008
Posts: 5
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Thanks for such a quick reply.
The user agent is blank. The IIS log entry looks like this: (I have obscured the IP addresses for privacy)
2008-01-31 21:20:46 208.109.***.*** GET /default.aspx - 80 - 206.251.***.*** - 302 0 0
2008-01-31 21:20:47 208.109.***.*** GET /favicon.ico - 80 - 206.251.***.*** - 200 0 0
I'm not certain it's a spider. I did a reverse DNS on the IP address, and it's an ISP in Pennsylvania. If you want to see the IP address (or anything else about this entry) I can email it to you.
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Rank: Newbie
Groups: Member
Joined: 2/1/2008
Posts: 5
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It may be a coincidence, but there is another entry from the same IP Address, about 15 minutes later. At that time, their User agent was:
Mozilla/5.0+(Windows;+U;+Windows+NT+5.1;+en-US;+rv:1.8.1.11)+Gecko/20071127+Firefox/2.0.0.11 200 0 0
Since it's the IP address of an ISP, I can't be certain it's the same person, but I don't get enough traffic that I would possibly get two unique visitors from the same ISP in the span of 15 minutes. I hope this provides a clue.
Some kind of extension/add-on in FireFox mucking things up? Perhaps a privacy or anonymous add-on? Just some thoughts on why FireFox would not provide a user agent.
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Rank: Administration
Groups: Administration
Joined: 5/27/2007
Posts: 24,095
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Hi,
FireFox extension would always be carried by FireFox, so it's unlikely that they would mess up UserAgent. One possibility is the IP address tha you see is a gateway/proxy IP address, there are multiple machines behind it.
Thanks
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Rank: Newbie
Groups: Member
Joined: 2/1/2008
Posts: 5
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Where do we go from here? Is this something you can correct in a new release? I realize I can ignore the error, but it would be nice to get this taken care of.
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Rank: Administration
Groups: Administration
Joined: 5/27/2007
Posts: 24,095
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We will look into it and see what we can do. But since it is not a critical issue, also because we can not see the problem here, so it's kind of like shooting in the dark for us. Thus we are unable to promise anything for now.
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Rank: Newbie
Groups: Member
Joined: 2/1/2008
Posts: 5
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I understand. Thank you.
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