Trying To Change The IP Address And The Hostname

Hi,

I tried to configure my ethernet interface on a Debian Wheezy VM, but I've a problem. When I try to restart /etc/init.d/networking, I've no error message.
But my eth1 interface isn't up and when I try to up it with : ifup eth1, it return me :

Code:

root@debian-main:/# ifup eth1
RTNETLINK answers: File exists
Failed to bring up eth1

My /etc/network/interface file is :

Code:

auto eth0
allow-hotplug eth0
iface eth0 inet dhcp


iface eth1 inet static
        address 192.168.10.1
        netmask 255.255.255.0
        gateway 192.168.10.254

Eth0 is my internet interface and eth1 is a local interface. I want to install a DNS and a DHCP server on eth1 to be able to connect client with this VM and give them an ip adress.

Thanks guys

Hi all

This is bothering me too much, please tell me how to change IP address of remote machine while using ssh successfully.

I follow these steps:
1. connect to remote server using 'ssh root@server'
2. Edit '/etc/sysconfig/network-scripts/ifcfg-eth0' file
3. issue 'service network restart' command... (at this point ssh connection gets hanged)
4. Break from hanged ssh connection (<ENTER>~.)
5. Wait for some time to let service restart
6. Then finally, ssh with new ip address.

All is fine, but last time, i did something wrong while assigning new IP address, and after service restart, remote server didn't get new ip address - and now i cant connect to remote server.

Fortunately, i had a friend there, who helped me correct the problem so that i can connect again.

But what to do when there is no one to help? Is there other way i should approach this problem?

Thanks

Hello, I have an expect script where I ssh to a remote host to determine the network configuration and get from the user the network interface card that should be used. From their response, I determine the subnet mask and save the information to a text file that is later transmitted back to my local host. This is all so that I can set up virtual IP aliasing and verify that the physical IP address of the local and remote host are on the same subnet prior to continuing with the setup. I am running the script on Linux, with expect version 5.45.

The code itelf works just fine, but I'm having some issues with how it displays on the screen. As you'll see below in the example, the default system prompt displays, as does the user input command that I'm sending to the shell from the expect script.

Is there a regular expression or something that I can write to prevent the prompt and command that I'm sending from printing to the screen? I know that it should be suppressed if I have an expect command following the Code:

send -s "\nread n_card?'Enter the network interface card number for this server (i.e. eth0):   '\r

command, but everything I have tried for strings and regular expressions to expect causes the netstat -rn output to not show up all of a sudden. I'm new to expect, so I'm not really sure why this is happening.

I would really appreciate any help/suggestions. Thanks for your time!

Part of the Script Code:
Code:

expect {
   -re $prompt {   ;# Send individual commands and get user input
        set timeout -1
        
        # Get partner hostname and put in vipsetup.txt file
        send -s "hostname > vipsetup.txt\r"  
        expect -re $prompt
        
        # Display the network routing info for the user and prompt for 
        # network interface card number
        send -s "print \"The network routing table for the $ptner server is displayed below:\n\" ; netstat -rn \r"
        
        expect -re "\r(.*):\r"
        send -s "\nread n_card?'Enter the network interface card number for this server (i.e. eth0):   '\r"
        interact "\r" return    ;# Wait for user input from read command
        send -- "\r"
        send -s "echo \$n_card >> vipsetup.txt\r"  
        
        # Obtain subnet mask information for partner based on network 
        # interface card number being used
        send -s "msk=\$(cat /etc/sysconfig/network-scripts/ifcfg-\$n_card | grep NETMASK)\r"
        send -s "msk=\$(echo \${msk#NETMASK=})\r"
        send -s "echo \$msk >> vipsetup.txt\r"
    }
    timeout {
        send_user "Connection to host $hostip timed out."
        exit 6 
    }
    eof {
        send_user "Connection to host $hostip failed."
        exit
    }
}

Script Output:
Code:

The network routing table for the PRIMARY server is displayed below:
 
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
10.105.65.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
0.0.0.0         10.105.65.1     0.0.0.0         UG        0 0          0 eth0
 [root@remotehost root]$
[root@remotehost root]$ ber for this server (i.e. eth0):   '              < 
Enter the network interface card number for this server (i.e. eth0):   eth0

Hi all

I am trying out this dhcp server setup on opensuse 12.1 but it does not seem to be working.

I have eth0 configured to be 192.168.10.1 in a /24 network.

I want to hand out the rest of the address in the same subnet as dhcp addresses. (So everything from 10.2 to 10.255). The default gw is defined as 192.168.10.1, and routing table looks correct. and I only have eth0.


When I start the dhcp, and connect it to the client machine, I see nothing on the wireshark trace. no DHCP discovery or ack messages. And the client machine just keeps trying boot from the network via the network interface. I know I got the right interface (there were blinky options in the bios that lets you identify the correct interface) and the cable is not a problem. (If the cable were a problem the client boot message would say "media fault ... please check media...") instead.

Here is my dhcpd.conf file. I went through man dhcpd already, and cleaned out everything that I apparently don't need. (The original file was copied from a more complicated setup that had multiple subnets and dhcp relays.)

Code:

###################simplfied 
linux-kzy1:/var/lib/dhcp/db # cat /etc/dhcpd.conf
authoritative;

ddns-update-style none;
ddns-updates off;

#Information about the host
subnet 192.168.10.0 netmask 255.255.255.0 {
  max-lease-time 600;
  default-lease-time 600;
  range 192.168.10.2 192.168.10.255;
}

group esx_gep{
  filename "pxelinux.0";
  next-server 192.168.10.1; 
  host testserver1 {hardware ethernet a0:d3:c1:f7:f2:64;}
}

this is what /var/log/message and /var/log/rc.dhcpd.log says:
Code:

**************var log message
Mar 19 18:42:17 linux-kzy1 dhcpd: For info, please visit https://www.isc.org/software/dhcp/
Mar 19 18:42:17 linux-kzy1 dhcpd: Not searching LDAP since ldap-server, ldap-port and ldap-base-dn were not specified in the config file
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 group decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 deleted host decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 new dynamic host decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 leases to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Listening on LPF/eth0/84:8f:69:cf:7c:41/192.168.10.0/24
Mar 19 18:42:17 linux-kzy1 dhcpd: Sending on   LPF/eth0/84:8f:69:cf:7c:41/192.168.10.0/24
Mar 19 18:42:17 linux-kzy1 dhcpd: Sending on   Socket/fallback/fallback-net
Mar 19 18:42:17 linux-kzy1 dhcpd[12233]: Starting ISC DHCPv4 4.x Server [chroot]..done
linux-kzy1:/home/test/Documents #


*****************var log rc.dhcpd.log
Mar 19 18:42:17 linux-kzy1 dhcpd: Internet Systems Consortium DHCP Server 4.2.2
Mar 19 18:42:17 linux-kzy1 dhcpd: Copyright 2004-2011 Internet Systems Consortium.
Mar 19 18:42:17 linux-kzy1 dhcpd: All rights reserved.
Mar 19 18:42:17 linux-kzy1 dhcpd: For info, please visit https://www.isc.org/software/dhcp/
Mar 19 18:42:17 linux-kzy1 dhcpd: Not searching LDAP since ldap-server, ldap-port and ldap-base-dn were not specified in the config file
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 group decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 deleted host decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 new dynamic host decls to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Wrote 0 leases to leases file.
Mar 19 18:42:17 linux-kzy1 dhcpd: Listening on LPF/eth0/84:8f:69:cf:7c:41/192.168.10.0/24
Mar 19 18:42:17 linux-kzy1 dhcpd: Sending on   LPF/eth0/84:8f:69:cf:7c:41/192.168.10.0/24
Mar 19 18:42:17 linux-kzy1 dhcpd: Sending on   Socket/fallback/fallback-net
Mar 19 18:42:17 linux-kzy1 dhcpd[12233]: Starting ISC DHCPv4 4.x Server [chroot]..done
linux-kzy1:/home/test/Documents #

not very interesting stuff or useful, but I found some other messages that is very interesting:

Code:

**********
#no free lease

linux-kzy1:/home/test/Documents # cat /var/log/messages | grep "free lease"
Mar 19 15:53:59 linux-kzy1 dhcpd: DHCPDISCOVER from a0:d3:c1:f7:f2:64 via eth0: network 192.168.10.0/24: no free leases
Mar 19 15:54:03 linux-kzy1 dhcpd: DHCPDISCOVER from a0:d3:c1:f7:f2:64 via eth0: network 192.168.10.0/24: no free leases
Mar 19 15:54:11 linux-kzy1 dhcpd: DHCPDISCOVER from a0:d3:c1:f7:f2:64 via eth0: network 192.168.10.0/24: no free leases
......
Mar 19 17:01:06 linux-kzy1 dhcpd: DHCPDISCOVER from a0:d3:c1:f7:f2:64 via eth0: network 192.168.10.0/24: no free leases
Mar 19 17:01:38 linux-kzy1 dhcpd: DHCPDISCOVER from a0:d3:c1:f7:f2:64 via eth0: network 192.168.10.0/24: no free leases
linux-kzy1:/home/test/Documents #

Which ties into my first question: dhcp no free lease: I googled a bit, I found a post from a guy on ubuntu who has the same error message and the suggested course of action is to change ownership of the lease file to dhcpd and give it 777 for permission. Which I thought is weird, because the lease file is automatically created by the dhcpd itself, so it really shouldn't be a permission issue shouldn't it? (Anyway, tried that didn't do a thing.) right now it is owned by root/root and has this permission: -rw-r--r--.

2nd question: once the client gets a reply from my dhcp server saying no free lease, does it remember this dhcp server as no free lease and does it persist throughout reboots? Because I tried rebooting the client a number of times and I don't see anything on the wireshark at all. You will notice the time stamp on the last "no free lease" message is not as late as the other messages from the var/log/messages or rc.dhcpd.log and I rebooted the client and the dhcp plenty of times since 17:01:38.



Thanks for all your help in advance everyone.

I have a shell script that currently changes the mac address of eth0 repeatedly. However, it does not change the public IP address, confirmed by wget -qO- ipinfo.io/ip .

PERIOD=10

while [ 1 ]
do
echo "Changing mac address..."
let lastup=`date +%s`
macchanger -A eth0
let diff=`date +%s`-$lastup
if [ "$diff" -lt "$PERIOD" ]
then
sleep $(($PERIOD-$diff))
echo "Changed mac address successfully."
echo
elif [ "$diff" -gt "$PERIOD" ]
then
echo "Command took longer than iteration period of $PERIOD seconds!"
fi
done

The script needs to change the IP Address statically.

Also, ultimately, what I am trying to accomplish, for security reasons, is to frequently and automatically change a computer's public IP address and mac address. This way, my office's computers, when using the Internet, has an additional form of protection.

Hi All,

I have a website hosted at some web hosting company. Let me call it ' http://www.example.com '.

I have installed bind9 in one of the local server (private IP), called ' ns.example.com '. I have named zone as ' example.com ', same as my website.

Following is a forward zone file for ' example.com ' in box with hostname ' ns.example.com '
Code:

$ cat db.example.com 

$TTL 86400 ; (1 day)
$ORIGIN example.com.

@ IN SOA ns.example.com. admin.example.com. (
    2015042601 ; serial YYYYMMDDnn
    14400      ; refresh (4 hours)
    1800       ; retry   (30 minutes)
    1209600    ; expire  (2 weeks)
    3600 )     ; minimum (1 hour)

@  IN NS ns.example.com.
ns IN A 192.168.1.7

localhost IN A 127.0.0.1
sql       IN A 192.168.1.100
ftp       IN A 192.168.1.101

Following is a reverse zone file for ' example.com ' in box with hostname ' ns.example.com '
Code:

$ cat db.192.168.1 

$TTL 86400 ; (1 day)
$ORIGIN 1.168.192.in-addr.arpa.

@ IN SOA ns.example.com. admin.example.com. (
    2015042601 ; serial YYYYMMDDnn
    14400      ; refresh (4 hours)
    1800       ; retry   (30 minutes)
    1209600    ; expire  (2 weeks)
    3600 )     ; minimum (1 hour)

@ IN NS  ns.example.com.
7 IN PTR ns.example.com.

100 IN PTR sql.example.com.
101 IN PTR ftp.example.com.

resolve.conf
Code:

$ cat /etc/resolv.conf

search example.com
nameserver 192.168.1.7

Everything works perfectly fine. Only problem is, this bind server is unable to resolve http://www.example.com, which is my actual website.

Code:

$ nslookup linuxquestions.org
Server:		192.168.1.7
Address:	192.168.1.7#53

Non-authoritative answer:
Name:	linuxquestions.org
Address: 75.126.162.205

$ nslookup example.com
Server:		192.168.1.7
Address:	192.168.1.7#53

*** Can't find example.com: No answer

My bind server is recursive, and I dont want to use other public dns servers. Also my root hints are latest.

How do I resolve my website IP address?

Thanks

NOTE: my actual website name is different. I have used example.com just for illustration only. My bind server will resolve real www.example.com.
Code:

$ nslookup example.com
Server:		192.168.1.7
Address:	192.168.1.7#53

Non-authoritative answer:
Name:	example.com
Address: 93.184.216.34

I just installed Redhat 7 and try to config the network , add the IP address to network card , but I got the problem.

I modify the file /etc/sysconfig/network-scripts/ifcfg-enp0s3 , the configuration is as below , and then reboot .

DEVICE="enp0s3"
NETBOOT="yes"
HWADDR="08:00:27:15:38:B7"
TYPE="Ethernet"
BOOTPROTO="none"
NAME="enp0s3"
UUID="462f4834-4fe7-43a7-84e7-83b2722e94c1"
ONBOOT="yes"
IPADDR="192.168.1.1"
NETMASK="255.255.255.0"

After reboot , I use "ip addr show" still not shown the ip address , the ip address is still blank , would advise what is wrong ? thanks

I am trying to set up Samba4 using the Sernet appliance. It is a Debian core.

I edited /etc/network/interfaces to set a static address for eth0. I used http://www.cyberciti.biz/faq/linux-c...ress-tutorial/ as a guide.

Now eth0 will not start on boot. Why?

Thanks!

Hi all,

I have a host#1 with ip=192.168.3.100 and a host#2 with ip=192.168.2.100. Both hosts are connected to some linux device with 2 interfaces : eth0 with ip=192.168.2.1 and eth1 with ip=192.168.3.1.

So host#1 is connected to eth1 and host#2 to eth0. I would like to ping host#2 from host#1 and vice versa. How can I do that ?

I tried :
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

but it didn't work

PS
This is my first post here, so please don't be very strict to me
Looking forward to hearing from anybody as I'm out of ideas...

BR,
Dmitry

hi guys,

on my centos 7 machine i was looking for

/etc/sysconfig/network-scripts/ifcfg.eth0 file

but there is only ifcfg-enp2s0

what is enp2s0? thought i had a standard ethernet card