I tried to capture DHCP Discovery through the tcpdump:
# ip l | grep enp5s0
3: enp5s0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
# tcpdump -ni enp5s0
tcpdump: enp5s0: That device is not up
# ip l s dev enp5s0 up
# ip l | grep enp5s0
3: enp5s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
# tcpdump -ni enp5s0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp5s0, link-type EN10MB (Ethernet), capture size 262144 bytes
Then I do
# dhclient enp5s0 -v
Internet Systems Consortium DHCP Client 4.3.5
Copyright 2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Listening on LPF/enp5s0/2c:fd:a1:c6:d6:13
Sending on LPF/enp5s0/2c:fd:a1:c6:d6:13
Sending on Socket/fallback
DHCPDISCOVER on enp5s0 to 255.255.255.255 port 67 interval 4
DHCPDISCOVER on enp5s0 to 255.255.255.255 port 67 interval 6
...
But there is nothing in tab with tcpdump. What could be the problem?
P.S. the same behavior is with ifup/ifdown.
