Failed to send 300 byte long packet over fallback interface (dhclient)
- 06 Mar 2017: Post was created (diff)
dhclient started complaining a lot recently:
dhclient[17182]: DHCPREQUEST on wlp2s0 to 10.10.3.1 port 67
kernel: [UFW AUDIT] IN= OUT=wlp2s0 SRC=10.10.3.227 DST=10.10.3.1 LEN=328 TOS=0x00 PREC=0x00 TTL=64 ID=56217 DF PROTO=UDP SPT=68 DPT=67 LEN=308
dhclient[17182]: send_packet: Operation not permitted
dhclient[17182]: dhclient.c:2593: Failed to send 300 byte long packet over fallback interface.
I have seen the send_packet: Operation not permitted messages before, and they have usually showed themselves when I’m blocking something I shouldn’t be blocking. Might have a little too strict iptables rules. But blocking the DHCP port 67 is usually not something I’d want to do.
I am using UFW for handling my iptables rules. As one of my first rules are
ufw deny out on wlp2s0, I need to place this one before it in the chain.
# ufw insert 1 allow out on wlp2s0 to any port 67 proto udp comment DHCP
Now my dhclient seems to be happy again
dhclient[17182]: DHCPREQUEST on wlp2s0 to 10.10.3.1 port 67
kernel: [UFW AUDIT] IN= OUT=wlp2s0 SRC=10.10.3.227 DST=10.10.3.1 LEN=328 TOS=0x00 PREC=0x00 TTL=64 ID=56842 DF PROTO=UDP SPT=68 DPT=67 LEN=308
dhclient[17182]: DHCPACK from 10.10.3.1
dhclient[17182]: bound to 10.10.3.227 -- renewal in 8268 seconds.
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