‘Login to Proxmox host failed’ – Why it happens and how to fix it?
The error ‘Login to Proxmox host failed’ can happen in different scenarios:
- When you try to access the Proxmox VE management console directly
- While integrating a third party module such as WHMCS into your Proxmox server
- During the management of a cluster of Proxmox nodes
Proxmox would just say “Login failed, please try again” and you may have no idea what went wrong.
Today we’ll see the 4 main reasons why we come across ‘login to Proxmox host failed’ error during our Outsourced Web Hosting Support services and how we fix each of them.
1. Login failed due to SSL problems
The default URL to access the Proxmox VE management console is https://IPaddress:8006/ . If you try to access it without secure protocol, the console will not load.
At times, when the SSL certificate has expired, there maybe issues accessing the Proxmox node. In some cases, a bug with Proxmox cause it not to detect the SSL settings.
To fix SSL issues, first confirm that the certificate has not expired and is working fine. If all fine, execute this command in the Proxmox machine:
pvecm updatecerts --force
This command will update and fix the issues related to Proxmox SSL certificate and you’d be able to access the node fine.
2. Firewall rules causing login failures
Firewall rules in the Proxmox node can cause login failures. While firewalls are important to secure a server, configuring the rules correctly is vital for proper server functioning.
Proxmox VE 4.x and later uses the following ports:
- Web interface at port 8006
- pvedaemon (listens only on 127.0.0.1) at port 85
- SPICE proxy at port 3128
- sshd at port 22
- rpcbind at port 111
In Proxmox servers where firewalls such as iptables is used, specifically allow these ports for proper functioning of the Proxmox server.
To allow the Proxmox ports, firewall rules have to be added in the Proxmox server for the corresponding ports:
For proper internal communication in the Proxmox server, a rule to accept loop-back interface connection should also be added.
In the case of third party modules such as WHMCS, Modulegarden, etc., it is important to ensure that the connectivity is proper between the two servers.
Use telnet command to check the connectivity to Proxmox node from the module server. This helps to know if the login failure is due to any connectivity problems.
Flushing the firewalls fully may resolve connectivity problems, but its not advisable for server security. That makes it important to allow the required connections while denying everything else.
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