# Hostname resolution



## balanga (Oct 6, 2014)

I understand that hostname resolution is done via /etc/resolv.conf, but how is this file populated during the installation process? 

When I boot up from a USB pendrive the file /etc/resolv.conf is linked to /tmp/bsdinstall_etc/resolv.conf and I can't figure out how this is eventually updated during the installation process..

I'm trying to create a bootable/networkable USB pendrive from a USB installation image and it almost works apart from hostname resolution...


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## kpa (Oct 6, 2014)

There are no reasonable defaults for the contents of the /etc/resolv.conf file, that's why it's not created during the install phase unless you set up the network interface with a static address and you then get asked for the details to fill in. On first boot on a newly installed system if DHCP is used dhclient(8) creates the file using the DNS information it gets from the DHCP server.


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## SirDice (Oct 6, 2014)

balanga said:
			
		

> I understand that hostname resolution is done via /etc/resolv.conf, but how is this file populated during the installation process?


When using DHCP it's the DHCP server that supplies the information and it's added automatically. If it's a static configuration you have to enter the DNS and domain information during the installation process. It's that information that's added.


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## balanga (Oct 6, 2014)

kpa said:
			
		

> There are no reasonable defaults for the contents of the /etc/resolv.conf file, that's why it's not created during the install phase unless you set up the network interface with a static address and you then get asked for the details to fill in. On first boot on a newly installed system if DHCP is used dhclient(8) creates the file using the DNS information it gets from the DHCP server.



I'm attempting to create a bootable/networkable USB pendrive  by manually going through the steps which are done by `bsdinstall`.  I knew that `dhclient` configured the IP address but wasn't sure how resolv.conf was updated - and still don't since at the time `bsdinstall` runs the file is linked to some other file.

I'm basically trying to figure out how `bsdinstall` does this.


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