Rejecting Blank Host

Question

Hello all, we have created an iRule that is suppose to block request to a website with no Host Header.  I've included the code below.  The rule appears to be working, but we are getting the following error in the BigIP log files:&nbsp;
&nbsp;TCL error: BlockNoHeader - expected integer but got "reject" while executing "HTTP::respond reject" &nbsp;
&nbsp;The iRule consist of this:
&nbsp;  when HTTP_REQUEST { 
&nbsp;if { [HTTP::host] equals "" } { 
&nbsp;       HTTP::respond reject } 
&nbsp;}&nbsp;
&nbsp;Any thoughts or suggestions, maybe we could be doing the block method better?&nbsp;
&nbsp;Thanks,
&nbsp;Bob

hoolio · Answer

Hi Bob, 
&nbsp;  
&nbsp; If you want to send a TCP reset to the client you can change HTTP::respond reject to just reject. 
&nbsp;  
&nbsp; Aaron

bob_10976 · Answer

Thanks for the quick reply Aaron.. Just to clarify the rule would look like this:&nbsp;
&nbsp;when HTTP_REQUEST { 
&nbsp;   if { [HTTP::host] equals "" } { 
&nbsp;     reject } 
&nbsp;}
&nbsp; 
&nbsp;Thanks,
&nbsp;Bob

hoolio · Answer

Exactly.  Did that work as you want? 
&nbsp;  
&nbsp; Aaron

bob_10976 · Answer

At first I thought that did the trick because I didn't see anything in this mornings logs.  I checked yesterdays logs and I can see:  local/tmm err tmm[4820]: 01220001:3: TCL error: Test_BlockNoHeader - expected integer but got "reject" while executing "HTTP::respond reject"&nbsp;
&nbsp;Any thoughts?

hoolio · Answer

Hi Bob, 
  
 I assume you were getting that error from the original version of the iRule.  Have you tried testing with this version which doesn't use HTTP::respond?

when HTTP_REQUEST {
   if { [HTTP::host] equals "" } {
      reject
   }
}

Aaron

Forum Discussion

Recent Discussions

Changes to DO and AS3 GitHub - no longer monitored

SSL Forward Proxy, iRules and Client Hello

monitor/healthcheck issue with envoy gateway

Recommendation for Adv. Lab

How to Verify config before loading to F5

Related Content

Convert 404s to Blank 200s

(HTTP) Redirection via Arbitrary Host Header

Certificate Automation for BIG-IP using CyberArk Certificate Manager, Self-Hosted

DevCentral Connects hosts Capture the Flag!

Modify blank URI