When it comes to hosting the WordPress blogs that you so dearly love and care, there’s nothing like CloudFlare. Hosting your WordPress blog on Cloudflare has invaluable benefits which are quite simply unparalleled. However, as with all the great services, there’s a bug that’s quite common but exponentially annoying: the Error 522.
As with all the other errors, the Error 522 can’t be traced back to a definite source. The factors behind it are many and to pinpoint any one reason would be foolhardy. This error can be experienced by the user as well as the admin who is in charge of curating the web blog. What triggers the CloudFlare Error 522 is the failure of establishing a TCP connection between CloudFlare server and the website’s origin server. When a user visits a CloudFlare enabled website, a connection has to be established between CloudFlare and website’s origin server. This happens via a 3-way handshake protocol. Here’s what it means:
- SYN: CloudFlare sends SYN packets to the origin server
- SYN+ACK: The host server responds with SYN+ACK
- ACK: The CloudFlare then sends ACK back to the host server
At this point the acknowledgements have been exchanged between server and CloudFlare and a connection is thus established. However, if no SYN+ACK has been received by the host server within 15 seconds of the SYN packets being sent, then the Error 522 comes into the picture.
Another possible cause for Error 522 is when the TCP connection has been established between CloudFlare and host server but the server is unable to get the ACK from the source and hence the connection times out resulting in Error 522.
How To Resolving the CloudFlare Error 522
Here’s a low-down of the other potential causes behind this notorious dampener:
- The Origin server becomes too overloaded to respond
- The firewall at the origin server blocking the requests being sent or packets being dropped within the host server’s network
- The origin server may be offline or the hostname is stored incorrectly in the DNS settings(i.e. The requests being some sent from us are to a wrong location)
- There is a network routing issue between us and the server
- The origin server has KeepAlives disabled
One of the ways of resolving this issue is to check if the web server is active and accepting HTTP requests before going further and also ensure if the DNS settings have been configured correctly.
- Another less reported issue is the CloudFlare’s page rule options that’s the cause of the pain caused. For this, once the page rule is removed, the problem is solved in most of the cases.
If you’re struck by any of the issues mentioned above, the solutions to get a quick fix are as follows:
The Origin server being too overloaded
For this, you can fix the issue by ensuring that the load on your server is kept within limits. From time to time, ensure that your load average is kept at an optimum level. The failure to do so would result in the server dropping requests. If you’re using Unix/Linux, you can check the load server by simply typing ‘w’ on the command line. Another command that may also come handy is the top command.
The optimum load criteria is a subject of much debate and depends on a great deal on the system and the software being run on it. However, load average of 10 to 20 is considered on the higher side. You can also contact your system administrator to be sure.
The origin has a rate-limiter or Firewall that blocks your request
One of the most common causes of 522 errors. The things to check are :
- Ensure that CloudFlare IPs, .htaccess, Iptables or your firewall are not being blocked
- Ensure that your host server isn’t rate limiting or blocking the IP requests from CloudFlare IPs and if so, make sure you whitelist the IP addresses mentioned here CloudFlare IPs.
As most of your traffic will flow from CloudFlare, the origin would see the requests coming from it. While there are only a handful of IP addresses to do so, the Firewalls at the origin are triggered mistaking the requests for a Distributed Denial of Service(DDOS) attacks among other risks. Apart from Firewalls, Rate limiters are known to do this. CPHulk, along with cPanel is known to do this along with other services out there. To ensure this doesn’t happen, have the IP addresses mentioned in the above link whitelisted or better, have the rate limiter disabled.
Network Issue between CloudFlare and Host server
As it is more difficult to troubleshoot this issue than the others, ensure that all the above issues have been checked for before we tackle this solution. If all the above mentioned solutions don’t yield any positive results, you can raise this issue with the CloudFlare support team. When raising this issue, keep in mind to provide the following information:
- Information on the course of action taken from your end
- An MTR traceroute from your host server to the CloudFlare IP addresses
The origin server has Keepalives disabled
CloudFlare uses the KeepAlive header to improve performance. When your host server has this disabled, the cloudflare error 522 would be returned in many instances.However, it’s highly unlikely that this may be an issue as all the major web servers have the KeepAlive function enabled but you can ensure if that is not the case.
Apart from this, you can also check if the Page rules configuration is another source of 522 errors. Removing the page rules configuration can also solve the 522 errors in many instances.
If none of the above solutions cut the ice for you, it’s a good idea to ring to the CloudFlare support and get your issue a dedicated solution.