Is there any relation between modprobe.conf file and network devices?

Yes, this file assigns a kernel module to each network device.
For Example:-
[root@localhost ~]# cat /etc/modprobe.conf
alias eth0 b44
Here, b44 is the kernel module for network device eth0.
We can confirm whether this module “b44” is present or not by the following command
[root@localhost ~]# lsmod |grep b44
b44 29005 0