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I got a Ubuntu Server 16.04 LTs, it's a VM on a ESX (VMware). This server was in dhcp config and it worked fine until today. (I know a server should be in static address but in my case, i don't really need to be static). Today, I restarted the server (the VM) and there is not more IPv4 for the server, only a IPv6.

I didn't change anything in the config, i will show you the differents files/configs that I think is usefull, if you need more just ask.

/etc/hosts

127.0.0.1       localhost
127.0.1.1       my_hostname

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

/etc/hostname

my_hostname

/etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

output from ifconfig command

eth0      Link encap:Ethernet  HWaddr 00:50:56:94:d1:ae
          adr inet6: fe80::250:56ff:fe94:d1ae/64 Scope:Lien
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Packets reçus:68852 erreurs:0 :0 overruns:0 frame:0
          TX packets:1120 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1000
          Octets reçus:5658008 (5.6 MB) Octets transmis:329017 (329.0 KB)

lo        Link encap:Boucle locale
          inet adr:127.0.0.1  Masque:255.0.0.0
          adr inet6: ::1/128 Scope:Hôte
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          Packets reçus:26990 erreurs:0 :0 overruns:0 frame:0
          TX packets:26990 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 lg file transmission:1
          Octets reçus:1997350 (1.9 MB) Octets transmis:1997350 (1.9 MB)

I try to release IPv4 dhclient -4 -r -v

Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/00:50:56:94:d1:ae
Sending on   LPF/eth0/00:50:56:94:d1:ae
Sending on   Socket/fallback

same for IPv6 dhclient -6 -r -v

Removed stale PID file
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on Socket/eth0
Sending on   Socket/eth0

**And it block here**

I also tried to ask a nex IP after dhclient -4 -v

DHCPDISCOVER on eth0 to 255.255.255.255 port 67
...
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

I know the IP address of the DHCP server, so I specified it, dhclient -4 -v -s IP_ADDRESS_DHCP_SERVER

DHCPDISCOVER on eth0 to IP_ADDRESS_DHCP_SERVER port 67
...
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

I don't know what to do any more, I tried to disable IPv6 but I just don't get any IP after that. I don't get it, it worked fine yesterday...

If you have an idea, I take it !
Thanks

yagmoth555
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Alexandre Serrano
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  • doesn't look like you get an ipv6 either. my guess is your DHCP server is down, or the "virtual" cable is not attached. most likely the ESX can disable a network connection as well, check on that end. you might be able to use ethtool to check the connection of the virtual lancable, though i didn't have done that yet. other than that, go for deeper troubleshooting, traffic dumps on both ends, and analyse the DHCP packages. – Dennis Nolte Jun 28 '19 at 13:35
  • Find the issue, I have got an IPv6 address (I even succed to connect to my VM in ssh with the IPv6), the problem was juste that there weren't enough IPv4 on available. The netword admin removde some old reservation and it worked ! I let this post if some I enough stupid like me to didn't find the problem:) – Alexandre Serrano Jun 29 '19 at 14:07
  • You should write your comment as an answer, and accept that answer, this way the question will be marked as solved. as for the IPv6, you were right, i misread the lien as link local somehow. – Dennis Nolte Jul 01 '19 at 07:11
  • Indeed, it's done :) Thanks for your help. – Alexandre Serrano Jul 01 '19 at 07:52

1 Answers1

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Find the issue, I have got an IPv6 address (I even succed to connect to my VM in ssh with the IPv6), the problem was juste that there weren't enough IPv4 on available. The netword admin removde some old reservation and it worked ! I let this post if some I enough stupid like me to didn't find the problem:)

Alexandre Serrano
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