Bug ID 560510: Invalid /etc/resolv.conf when more than one DNS servers are set and MCPD is down.

Last Modified: May 29, 2024

Affected Product(s):
BIG-IP LTM, MA-VE(all modules)

Known Affected Versions:
11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.1 HF10, 11.5.1 HF11, 11.5.2 HF1, 11.5.3 HF1, 11.5.3 HF2, 11.5.4 HF1, 11.5.4 HF2, 11.4.1, 11.6.0, 11.6.1, 11.6.2, 11.6.3,,,,, 11.6.4, 11.6.5,,,, 12.0.0, 12.0.0 HF1, 12.1.0 HF1, 12.0.0 HF2, 12.1.0 HF2, 12.1.1 HF1, 12.1.1 HF2, 12.1.2 HF1, 12.1.2 HF2

Fixed In:
12.1.0, 12.0.0 HF3, 11.6.1 HF2, 11.5.4 HF3

Opened: Dec 02, 2015

Severity: 3-Major


When MCPD is not in the running state, dhclient directly writes domain-name-server information into /etc/resolv.conf. If multiple domain-name-servers are given by DHCP server, they are written in the incorrect format with multiple domain-name-servers in a single line comma-separated. Each domain-name-servers entry should be written in a single line with "nameserver" prefix.


Domain name resolution doesn't work.


- MCPD is not in the running state. - DHCP is enabled. - DHCP server has provided multiple domain-name-server entries in the lease.


Bring up MCPD which would write the resolv.conf in the correct format. Alternatively, user can manually modify /etc/resolv.conf to write multiple nameserver entry one per line.

Fix Information

DHCP will now write a single nameserver per line in /etc/resolv.conf when multiple nameservers are configured in DHCP.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips