DNS Resolution

Domain Name System (DNS) resolution is critical for Veeam Backup & Replication deployment (VBR) and configuration. VMware components must be accessible via both forward (A) and reverse (PTR) lookups. If not some Veeam components may not work correctly.

If DNS resolution is not available you may add VMware vCenter, ESXi and managed Veeam servers to the local hosts file on all managed Veeam servers. When using this workaround it is recommended to add both short name and fully qualified domain name in the hosts file. DNS should be the preferred option.

When ESXi hosts are added to vCenter it is recommended to use FQDN. When backing up using "network" transport mode (NBD), the FQDN is returned via VMware API for Data Protection (VADP) so the backup proxy server must be able to resolve the FQDN via DNS. Using the hosts file the data transport path can be altered for NBD transfers.

Please see the below example.

Example hosts file

10.0.4.10    vcenter    vcenter.example.com

# 10.0.4.21    esx1    esx1.example.com # commented out management interface
# 10.0.4.22    esx2    esx2.example.com # commented out management interface

10.255.4.21    esx1    esx1.example.com # dedicated 10 GbE backup network
10.255.4.22    esx2    esx2.example.com # dedicated 10 GbE backup network

To explicitly alter the data transport path, the hosts file must be deployed on all backup proxy servers. For easier management, please see the Carbon module and Set-HostsEntry by Aaron Jensen.