Why HTTP GET works but POST doesn't?

Hey all,

We’ve got a situation where two SLES 10 servers (Server A and Server B) are sitting next to each other behind a CSS load-balancer. Server B needs to POST data to Server A as part of an application function. For some reason, from Server B, we are able to successfully make HTTP GET calls to Server A, but HTTP POST calls to Server A fail.

I am relatively new to Linux and was wondering where to start troubleshooting this? Maybe a good methodology and some useful tools would be very helpful… how would you guys start digging into this?

TIA!
B

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Does your application on ServerA support POST? If your application
doesn’t look for POST variables but does look for GET variables then
that’s not going to ever work unless you somehow make it support the
other or make your POST variables move over to GET variables.

Good luck.

shdowflare wrote:
> Hey all,
>
> We’ve got a situation where two SLES 10 servers (Server A and Server B)
> are sitting next to each other behind a CSS load-balancer. Server B
> needs to POST data to Server A as part of an application function. For
> some reason, from Server B, we are able to successfully make HTTP GET
> calls to Server A, but HTTP POST calls to Server A fail.
>
> I am relatively new to Linux and was wondering where to start
> troubleshooting this? Maybe a good methodology and some useful tools
> would be very helpful… how would you guys start digging into this?
>
> TIA!
> B
>
>
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Sorry, I first should have mentioned: yes, it does support POST. In fact, POST’ing works fine for traffic coming in through the load-balancer. It’s just traffic originating from this box it seems.

How can I start to methodically test this?

Thanks,
Brian

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LAN trace to see what’s different when traffic comes from the server vs.
your load balancer? The application should have logs as well. If
nothing else check the Apache web server logs… they can be helpful
(access_log probably, error_log perhaps).

Good luck.

shdowflare wrote:
> Sorry, I first should have mentioned: yes, it does support POST. In
> fact, POST’ing works fine for traffic coming in through the
> load-balancer. It’s just traffic originating from this box it seems.
>
> How can I start to methodically test this?
>
> Thanks,
> Brian
>
>
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With Firefox run the same page and check the error console.
cross server POST isn’t always allowed anymore depending on the
configuration. I’m running into this problem currently running
Javascript/JSTL. I’m looking into something called JSON to accomplish it.