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justin_westover's avatar
justin_westover
Icon for Nimbostratus rankNimbostratus
Jul 09, 2014

HTTP Monitor not working

I have a very simple HTTP monitor configured that isn't working. When looking in the IIS logs the F5 isn't sending the send string and I can change the send string to anything "GET /blablabla" and the node continues to stay up. I'm running v11.4.1. The configuration of the monitor is as such:

 

ltm monitor http aoc-web-http-10000 { defaults-from http destination *:ndmp interval 5 send "GET /css.htm" time-until-up 0 timeout 16

 

I do have an alias port configured for 10000 which for some reason doesn't show in this configuration but it is set. The only way I can take the node down is to setup a receive string that is incorrect but I don't believe I should have to have a receive string in order to verify if the server is responding on port 10000 and the F% is getting a response from the send string. If I telnet from the F5 to the server and issue the same GET query it works but the monitor doesn't. Some help would be really nice, i'm sure i'm missing something small.

 

application delivery
deployment
LTM
TMSH

7 Replies

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  • uni_87886's avatar
    uni_87886
    Icon for Cirrostratus rankCirrostratus
    Jul 09, 2014

    You will need a receive string configured - a string which must be in the response. Without it, all you're really doing is checking that the TCP connection succeeds. You could start with something simple like "200 OK"

     

    • justin_westover's avatar
      justin_westover
      Icon for Nimbostratus rankNimbostratus
      Jul 09, 2014
      So I have tried putting the receive string in but then I have the opposite problem and the node stays down. I setup a receive string to look for "200 OK" (no quotes) and also for "CSS Test file" as you will see below, this string is returned in the body of the GET query. I have included a telnet from the F5 on port 10000 and then a GET and the reply from the server. What would you match in this case? [root@F5_01:Active:Changes Pending] config telnet 172.16.101.65 10000 Trying 172.16.101.65... Connected to 172.16.101.65. Escape character is '^]'. GET /css.htm CSS Test file Connection closed by foreign host. If I match 200 OK or CSS Test file the node stay down until I remove the receive string. Thoughts?
    • uni_87886's avatar
      uni_87886
      Icon for Cirrostratus rankCirrostratus
      Jul 09, 2014
      Is this an IIS server? You should really put the HTTP version in your GET request: "GET /css.htm HTTP/1.0" or better yet "GET /css.htm HTTP/1.1\r\nHost: www.myhost.com\r\nConnection: close\r\n\r\n"
  • uni's avatar
    uni
    Icon for Altostratus rankAltostratus
    Jul 09, 2014

    You will need a receive string configured - a string which must be in the response. Without it, all you're really doing is checking that the TCP connection succeeds. You could start with something simple like "200 OK"

     

    • justin_westover's avatar
      justin_westover
      Icon for Nimbostratus rankNimbostratus
      Jul 09, 2014
      So I have tried putting the receive string in but then I have the opposite problem and the node stays down. I setup a receive string to look for "200 OK" (no quotes) and also for "CSS Test file" as you will see below, this string is returned in the body of the GET query. I have included a telnet from the F5 on port 10000 and then a GET and the reply from the server. What would you match in this case? [root@F5_01:Active:Changes Pending] config telnet 172.16.101.65 10000 Trying 172.16.101.65... Connected to 172.16.101.65. Escape character is '^]'. GET /css.htm CSS Test file Connection closed by foreign host. If I match 200 OK or CSS Test file the node stay down until I remove the receive string. Thoughts?
    • uni's avatar
      uni
      Icon for Altostratus rankAltostratus
      Jul 09, 2014
      Is this an IIS server? You should really put the HTTP version in your GET request: "GET /css.htm HTTP/1.0" or better yet "GET /css.htm HTTP/1.1\r\nHost: www.myhost.com\r\nConnection: close\r\n\r\n"
  • Henrik_Gyllkran's avatar
    Henrik_Gyllkran
    Icon for Nimbostratus rankNimbostratus
    Jul 09, 2014

    Typically you need to add codes for carriage return and new line on the send string. Try setting the send string to this: GET /css.htm\r\n\r\n