Starting isc-dhcp-server fails!

[bahador_b_92]

Hi,

I'm trying to set up a rouge AP on my Kali Sana 64-bit running as a virtual machine on virtualbox and I get to a point where I can't start my DHCP Server.

[....] Starting isc-dhcp-server (via systemctl): isc-dhcp-server.serviceJob for isc-dhcp-server.service failed because the control process exited with error code. See "systemctl status isc-dhcp-server.service" and "journalctl -xe" for details.
failed!

This is the report I get by running the command

systemctl status isc-dhcp-server.service

:

● isc-dhcp-server.service - LSB: DHCP server
Loaded: loaded (/etc/init.d/isc-dhcp-server; bad; vendor preset: enabled)
Active: failed (Result: exit-code) since Mon 2016-01-25 02:25:18 CET; 45s ago
Docs: man:systemd-sysv-generator(8)
Process: 2011 ExecStart=/etc/init.d/isc-dhcp-server start (code=exited, status=1/FAILURE)

Jan 25 02:25:18 myvkali systemd[1]: Starting LSB: DHCP server...
Jan 25 02:25:18 myvkali dhcpd[2017]: Internet Systems Consortium DHCP Serve....3
Jan 25 02:25:18 myvkali dhcpd[2017]: Copyright 2004-2015 Internet Systems C...m.
Jan 25 02:25:18 myvkali dhcpd[2017]: All rights reserved.
Jan 25 02:25:18 myvkali dhcpd[2017]: For info, please visit https://www.isc...p/
Jan 25 02:25:18 myvkali isc-dhcp-server[2011]: dhcpd service already running...!
Jan 25 02:25:18 myvkali systemd[1]: isc-dhcp-server.service: Control proces...=1
Jan 25 02:25:18 myvkali systemd[1]: Failed to start LSB: DHCP server.
Jan 25 02:25:18 myvkali systemd[1]: isc-dhcp-server.service: Unit entered f...e.
Jan 25 02:25:18 myvkali systemd[1]: isc-dhcp-server.service: Failed with re...'.
Hint: Some lines were ellipsized, use -l to show in full.

This is the contents of my

dhcpd.conf

file:

authoritative;
default-lease-time 600;
max-lease-time 7200;
subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.1;
option subnet-mask 255.255.255.0;
option domain-name "freewifi";
option domain-name-servers 192.168.1.1;
range 192.168.1.2 192.168.1.254;
}

[Fuzzer]

You probably forgot to type the interface in /etc/default/isc-dhcp-server.

[bahador_b_92]

You probably forgot to type the interface in /etc/default/isc-dhcp-server.

Your assumption was right, however even with adding "at0" to interfaces, I still get the same error.

I will simply put the full steps that I do here:

airmon-ng start wlan0
airmon-ng check kill
airbase-ng -c 11 -e freewifi wlan0mon

ifconfig at0 192.168.1.1 netmask 255.255.255.0
ifconfig at0 mtu 1400
route add -net 192.168.1.0 netmask 255.255.255.0 gw 192.168.1.1
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p udp -j DNAT --to 192.168.1.0
iptables -P FORWARD ACCEPT
iptables --append FORWARD --in-interface at0 -j ACCEPT
iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE
iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 10000

touch /var/lib/dhcp/dhcpd.leases
dhcpd -cf /etc/dhcpd.conf -pf /var/run/dhcpd.pid at0
/etc/init.d/isc-dhcp-server start

[Fuzzer]

Make sure the interfaces are up.
The service doesn't start because you already started dhcpd in the previous command.
The conf file is normally under /etc/dhcp/dhcpd.conf
Please edit that file and follow the steps below:

# pgrep dhcpd | xargs kill -9
# rm /var/run/dhcpd.pid
# systemctl start isc-dhcp-server

[bahador_b_92]

The interfaces are all up.

So I moved my /etc/dhcpd.conf to /etc/dhcp/dhcpd.conf after configuring the iptables and then did the following:

dhcpd -cf /etc/dhcp/dhcpd.conf -pf /var/run/dhcpd.pid at0
pgrep dhcpd | xargs kill -9
rm /var/run/dhcpd.pid
systemctl start isc-dhcp-server

I then checked if the DHCP server was running and it was!

However I don't get an internet connection on the client that connects to the Fake AP and it is very unstable (it keeps connecting/disconnecting). I am able to ping out of the client to 4.2.2.4 on the short time frame until I lose connectivity and there is no "freewifi" on my list anymore.

This also keeps popping up on my airbase terminal window.

Client XX:XX:XX:XX:XX:XX associated (unencrypted) to ESSID: "freewifi"

I also noticed a very strange behaviour right after starting airbase which is I get two ESSIDs broadcastet. One being "freewifi" and the other named "default". I have no idea where it comes from!!!

I'm using a TL-WN722N btw.

[Fuzzer]

You don't have to start the program with "dhcpd -cf ..." if you intend to start the dhcp service.
It is either one or the other.

In regards to the "default" ESSID there was a bug opened for it:
https://trac.aircrack-ng.org/ticket/1647

I don't know if it is already included in the kali package.

[mmusket33]

Reference the dual ESSID bug read thru these links


http://forum.aircrack-ng.org/index.p...ic,1164.0.html


http://forum.aircrack-ng.org/index.p...ic,1170.0.html


MTeams

[012skp]

Did you got the solution for you problem @bahador_b_92?. I am also facing the same problem. My phones are able to connect to Access Point but they get disconnected after few seconds. They automatically connnect and after a few seconds disconnect. This keeps happening for hours. My lease-time is same as you. In 1 minute my moblie connects and disconnects around 10 times. Please help...!!! Thank you

[mmusket33]

MTeams is unsure if this will be helpful however if you are using Network Manager(NM) to provide the internet connection(IC) then you are killing NM function when you evoke airmon-ng check kill.

If you do not provide internet access you can setup a rogue AP and pass the phish onto a phishing page BUT you cannot pass the client on to internet access if you kill NM.

Accessing the internet on one device and setting up a rogue AP on another device can be done. Read thru the comments in the netmanmac thread for starters.

MTeams