Re: ACE sending malformed requests?

cstockwe · ‎10-16-2008

Hi,

Our ACE has several contexts, and in one of them we are seeing a single probe fail at random times, to a single particular rserver.

The logs of the ACE and the affected rserver at the same time are:

ACE logs:

%ACE-3-251010 Health probe failed for server 10.254.20.52 on port 80, received invalid status code

%ACE-3-251010 Health probe failed for server 10.254.20.52 on port 80, server reply timeout

rserver log:

[Mon Oct 13 18:02:12 2008] [error] [client 10.254.20.11] Client sent malformed Host header

[Mon Oct 13 19:35:37 2008] [error] [client 10.254.20.11] Client sent malformed Host header

[Mon Oct 13 20:32:30 2008] [error] [client 10.254.20.11] request failed: error reading the headers

[Mon Oct 13 21:36:22 2008] [error] [client 10.254.20.11] request failed: error reading the headers

The strange thing is that it is always the same target rserver that reports this error. Naturally, I've asked the server admins to look at this rserver, but they've seen the 'client request' errors in their logs and are suggesting the ACE is at fault.

This rserver also hosts other IP addresses that are used in the same context in different serverfarms - and it behaves as normal without error....it is just this single destination IP that seems to have a problem. Other IPs in the same serverfarm are ok.

Are there any more in-depth checks that I can do at the ACE level to verify that all is OK with the ACE?

The probe is setup like:

probe http 80-checker

interval 10

passdetect interval 3

request method get url /ping

expect status 200 200

Thanks

Cameron

Syed Iftekhar Ahmed · ‎10-16-2008

I would like you to run sniffer on the Rserver and look into the HTTP Header of Probe request from ACE.

Check if the parameters expected by the RServer are in line with the http request used by ACE probe.

For example if RServer is expecting "www.xyz.com" as HOST then is ACE really using

"HOST:www.xyz.com" in the HTTP request header.

Thanks

Syed Iftekhar Ahmed