400 Bad Request Your browser sent a request that this server could not understand.

[pppplus]

Hi

For one user on a server, visitors have a lot of 400 Bad Request.
I don't find why.

If I open too quickly several pages, I've this error 400
I don't know where to search now.

I use CSF firewall, but same problem when I disable it.

Configuration :
php 5.6
ServerAlias *.|DOMAIN| in httpd.conf customisation



It's seems there is a limitation in the user... but I don't see any limit.

If I navigate on another domain (other user account) in the same server, no problem.




So, how to investigate ?
Thanks for your help.

 

[Richard G]

Is it only 400 or 400.1 or 400.2 or something like that?

It can be several things.

ServerAlias *.|DOMAIN| in httpd.conf customisation

Explain this please. Did you make some kind of customisation yourself? Is this only for this domain?

You might want to have a look in the log if you can find more there.
/var/log/httpd/error.log
/var/log/httpd/domains/userdomain.error.log
/var/log/httpd/domains/userdomain.log

 

[pppplus]

Hi

Thanks for your reply.
How to see if it's 400.1 or else ?
I see only 400 on the message.

=> ServerAlias *.|DOMAIN| in httpd.conf customisation
It's for accept all subdomain, without create them.
(it's a web service, where all customers have their own subdomain).

=> /var/log/httpd/error.log
nothing (i've error page, without any new line in it)

=> /var/log/httpd/domains/userdomain.error.log
only one line with error 400

=> /var/log/httpd/domains/userdomain.log
nothing (i've error page, without any new line in it)

 

[Richard G]

I see only 400 on the message.

If it only says 400 then it's 400.

If it only happens with one user, maybe he has some .htaccess redirect present or something.
Hard to say.
Maybe somebody else have an idea about it.

 

[pppplus]

Someone for another idea ??

Thanks

 

[pppplus]

Hi

Always the same problem.
But I just see today, that's there is no problem on Chrome, Opera, Edge.
The problem is only on Firefox.

That's really strange. Some user reports me the same problem (but I don't know if only on FF or not), and I've no idea how to find the problem.
I've found no error on logs.

Cache, cookies, history are deleted

 

[factor]

Look through this

I keep getting: Bad Request Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit(print page) | Firefox Support Forum | Mozilla Support

support.mozilla.org

could be this

Bad Request, Your browser sent a request that this server could not understand

There are two application servers and a switch. When i access application by using application server ip it works fine. However if i use switch ip in my url Bad request error throws up only for fir...

stackoverflow.com

Is this server all up to date?

 

[pppplus]

Thanks.
I delete manually cookies, and it works again.

That's very strange, because, my cache, cookies... have been deleted several times before this time.

So, I will see next time.