Failed to send 300 byte long packet over fallback interface

While reviewing the SysLog messages on my Linux Debian (v8 Jessie) server I noticed that the following error is flooding my logs:

dhclient.c:2243: Failed to send 300 byte long packet over fallback interface.
send_packet: Operation not permitted

After investigation it turned out that my local firewall was a bit to restrictive dropping outgoing DHCP packets. 

The solution is simple, just add the following statement to your iptables: 

iptables -A OUTPUT -p udp -o eth0 --dport 67 --sport 1024:65535 -j ACCEPT


About Normen 17 Articles
Normen is a freelance senior network security engineer specialised in Check Point Technologies solutions. If you like his articles you can buy him an espresso here

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