CentOS 6 and 7 / RHEL Persistent DHCP Solution

It is very silly but the default on the ifup-eth script tells dhclient ( the program that obtains a DHCP IP address if you have selected DHCP in your ifcfg-eth* config file) to EXIT / QUIT if the first attempt to obtain a lease fails.

No amount of dhclient.conf settings will fix this because if dhclient is started with -1 (which it is by default) then dhclient will quit.

This is obviously very bad for MOST cases.  Say for example you have a power outage or you initially power on the system, if for some reason the link takes a few more seconds to come up, dhclient has probably already quit being unable to obtain a lease the first time.

So the option to set in your ifcfg-eth0 config file to solve the dhclient persistent issue:

PERSISTENT_DHCLIENT=1

The difference in how dhclient is started now looks like this:

/sbin/dhclient -H hostname -q -lf /var/lib/dhclient/dhclient-eth0.leases -pf /var/run/dhclient-eth0.pid eth0

If you don't have the option above you will see a "-1" which indicates that it would quit if the first lease attempt fails:

/sbin/dhclient -H hostname -1 -q -lf /var/lib/dhclient/dhclient-eth0.leases -pf /var/run/dhclient-eth0.pid eth0

 

If you are looking for the equivalent Debian/Ubuntu/Mint solution then check this dhclient solution.


Tags:

centos, rhel, persistent, dhcp, solutionit, default, ifup, eth, dhclient, obtains, ip, selected, ifcfg, config, obtain, lease, fails, conf, settings, outage, initially, unable, persistent_dhclient, sbin, hostname, lf, var, lib, leases, pf, pid, quot, indicates,

Latest Articles

  • Grandstream Phone Vulnerability Security Issue Remote Backdoor Connection to 207.246.119.209:3478
  • Linux How to Check Which NIC is Onboard eth0 or eth1 Ubuntu Centos Debian Mint
  • VboxManage VirtualBox NAT Network Issues Managment Troubleshooting
  • Dell PowerEdge Server iDRAC Remote KVM/IP Default Username, Password Reset and Login Information Solution
  • Nvidia Tesla GPUs K40/K80/M40/P40/P100/V100 at home/desktop hacking, cooling, powering, cable solutions Tutorial AIO Solutions
  • Stop ls in Linux Debian Mint CentOS Ubuntu from applying quotes around filenames and directory names
  • Thunderbird Attachment Download Error Corrupt Wrong filesize of 29 or 27 bytes Solution
  • Generic IP Camera LAN Default IP Settings DVR
  • Ubuntu Debian Mint Linux How To Update Initramfs Manually update-initramfs
  • Enable Turbo Mode for CPU Ubuntu Linux Mint Debian Redhat
  • docker / kubernetes breaks Proxmox QEMU KVM Bridge VMs
  • How To Change Storage Location in Docker.io
  • RTL8812BU and RTL8822BU Linux Driver Ubuntu Setup Archer T3U Plus
  • Kazam video blank/high size and not working when recording solution
  • Cisco UC CME How To Enable Licensed Features
  • from pip._internal.cli.main import main File "/usr/local/lib/python3.5/dist-packages/pip/_internal/cli/main.py", line 60 sys.stderr.write(f"ERROR: {exc}") from pip._internal.cli.main import main File "/usr/local/lib/python3.5/dist-packag
  • ModuleNotFoundError: No module named 'pip._internal' solution python
  • grub blank screen how to manually boot kernel and initrd Linux Ubuntu Debian Centos won't boot solution
  • Cisco Switch / Router How To Restore Factory Default Settings
  • Cisco 2900 3900 Router Password Reset How To Reset Enable Password