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Gregory P. Ennis

2017-Jan-14 19:59 UTC

[CentOS] Centos 7 dhcpd failure to allow a 2nd network over same interal nic

Everyone,

I am trying to set up a second internal network  (192.168.0.0/24) and
have not been able to get dhcp to start when I have the following in my
dhcpd.conf file :

subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.110 192.168.0.130;
        option subnet-mask 255.255.255.0;
        option broadcast-address 192.168.0.255;
        option routers 192.168.0.1;
        option domain-name-servers 192.168.0.1;
}

When i remove the above from dhcpd.conf dhcpd works perfectly

I have my internal nic card set with two ip addresses one of which is
192.168.0.1. the other address is my standard internal network address.

I have also set up the domain server to allow access from
192.168.0.0/24, and the firewall allows internal access to the same
subnet.

The error that I get is the following :

Job for dhcpd.service failed because the control process exited with error code.
See "systemctl status dhcpd.service" and "journalctl -xe"
for details.

When I evaluate journalctl -xe the following is obtained :

dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Not searching LDAP since ldap-server, ldap-port and
ldap-base-dn were not specified in the config file
dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Wrote 0 deleted host decls to leases file.
dhcpd[18763]: Wrote 0 new dynamic host decls to leases file.
dhcpd[18763]: Wrote 2 leases to leases file.
dhcpd[18763]: Interface enp0s29u1u2 matches multiple shared networks
dhcpd[18763]: 
dhcpd[18763]: This version of ISC DHCP is based on the release available
dhcpd[18763]: on ftp.isc.org.  Features have been added and other
changes
dhcpd[18763]: have been made to the base software release in order to
make
dhcpd[18763]: it work better with this distribution.
dhcpd[18763]: 
dhcpd[18763]: Please report for this software via the CentOS Bugs
Database:
dhcpd[18763]:     http://bugs.centos.org/
dhcpd.service: main process exited, code=exited, status=1/FAILURE
dhcpd[18763]: 
systemd[1]: Failed to start DHCPv4 Server Daemon.

When I review the information about dhcpd it appears that it can manage
the ip addresses for two networks on different nic cards, but is there a
problem in having it manage two networks on the same nic card?

Does anyone have any ideas?  Would sure appreciate your help.

Greg Ennis



-- 
Greg Ennis
PoMec Corporation
www.PoMec.Net

James Hogarth

2017-Jan-14 21:12 UTC

head link

[CentOS] Centos 7 dhcpd failure to allow a 2nd network over same interal nic

On 14 Jan 2017 8:01 pm, "Gregory P. Ennis" <PoMec at pomec.net>
wrote:

Everyone,

I am trying to set up a second internal network  (192.168.0.0/24) and
have not been able to get dhcp to start when I have the following in my
dhcpd.conf file :

subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.110 192.168.0.130;
        option subnet-mask 255.255.255.0;
        option broadcast-address 192.168.0.255;
        option routers 192.168.0.1;
        option domain-name-servers 192.168.0.1;
}

When i remove the above from dhcpd.conf dhcpd works perfectly

I have my internal nic card set with two ip addresses one of which is
192.168.0.1. the other address is my standard internal network address.

I have also set up the domain server to allow access from
192.168.0.0/24, and the firewall allows internal access to the same
subnet.

The error that I get is the following :

Job for dhcpd.service failed because the control process exited with error
code. See "systemctl status dhcpd.service" and "journalctl
-xe" for details.

When I evaluate journalctl -xe the following is obtained :

dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Not searching LDAP since ldap-server, ldap-port and
ldap-base-dn were not specified in the config file
dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Wrote 0 deleted host decls to leases file.
dhcpd[18763]: Wrote 0 new dynamic host decls to leases file.
dhcpd[18763]: Wrote 2 leases to leases file.
dhcpd[18763]: Interface enp0s29u1u2 matches multiple shared networks
dhcpd[18763]:
dhcpd[18763]: This version of ISC DHCP is based on the release available
dhcpd[18763]: on ftp.isc.org.  Features have been added and other
changes
dhcpd[18763]: have been made to the base software release in order to
make
dhcpd[18763]: it work better with this distribution.
dhcpd[18763]:
dhcpd[18763]: Please report for this software via the CentOS Bugs
Database:
dhcpd[18763]:     http://bugs.centos.org/
dhcpd.service: main process exited, code=exited, status=1/FAILURE
dhcpd[18763]:
systemd[1]: Failed to start DHCPv4 Server Daemon.

When I review the information about dhcpd it appears that it can manage
the ip addresses for two networks on different nic cards, but is there a
problem in having it manage two networks on the same nic card?

Does anyone have any ideas?  Would sure appreciate your help.


Can you be a little clearer in what you're trying to do, as in the end goal
you are trying to reach?

Having dhcp for two different networks on the same physical network is just
not going to work in any sane fashion...

If you want to serve different dhcp pools to different physical networks
then you could do that via vlan and trunking from the switch to the server
or just ip-helper configuration on the router between the network
boundaries.

Gregory P. Ennis

2017-Jan-14 23:23 UTC

head link

[CentOS] Centos 7 dhcpd failure to allow a 2nd network over same interal nic

Everyone,

I am trying to set up a second internal network  (192.168.0.0/24) and
have not been able to get dhcp to start when I have the following in my
dhcpd.conf file :

subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.110 192.168.0.130;
        option subnet-mask 255.255.255.0;
        option broadcast-address 192.168.0.255;
        option routers 192.168.0.1;
        option domain-name-servers 192.168.0.1;
}

When i remove the above from dhcpd.conf dhcpd works perfectly

I have my internal nic card set with two ip addresses one of which is
192.168.0.1. the other address is my standard internal network address.

I have also set up the domain server to allow access from
192.168.0.0/24, and the firewall allows internal access to the same
subnet.

The error that I get is the following :

Job for dhcpd.service failed because the control process exited with error
code. See "systemctl status dhcpd.service" and "journalctl
-xe" for details.

When I evaluate journalctl -xe the following is obtained :

dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Not searching LDAP since ldap-server, ldap-port and
ldap-base-dn were not specified in the config file
dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
dhcpd[18763]: All rights reserved.
dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[18763]: Wrote 0 deleted host decls to leases file.
dhcpd[18763]: Wrote 0 new dynamic host decls to leases file.
dhcpd[18763]: Wrote 2 leases to leases file.
dhcpd[18763]: Interface enp0s29u1u2 matches multiple shared networks
dhcpd[18763]:
dhcpd[18763]: This version of ISC DHCP is based on the release available
dhcpd[18763]: on ftp.isc.org.  Features have been added and other
changes
dhcpd[18763]: have been made to the base software release in order to
make
dhcpd[18763]: it work better with this distribution.
dhcpd[18763]:
dhcpd[18763]: Please report for this software via the CentOS Bugs
Database:
dhcpd[18763]:     http://bugs.centos.org/
dhcpd.service: main process exited, code=exited, status=1/FAILURE
dhcpd[18763]:
systemd[1]: Failed to start DHCPv4 Server Daemon.

When I review the information about dhcpd it appears that it can manage
the ip addresses for two networks on different nic cards, but is there a
problem in having it manage two networks on the same nic card?

Does anyone have any ideas?  Would sure appreciate your help.


Can you be a little clearer in what you're trying to do, as in the end goal
you are trying to reach?

Having dhcp for two different networks on the same physical network is just
not going to work in any sane fashion...

If you want to serve different dhcp pools to different physical networks
then you could do that via vlan and trunking from the switch to the server
or just ip-helper configuration on the router between the network
boundaries.

James,

Sorry about the clarity... I will try again.  The man pages and examples
in Centos 7 demonstrate the ability to have two networks on the same
dhcpd server, but I did not identify specifically identify that any
reference to having both networks on one network card.  So far you are
obviously correct that this can not be done.  

I am trying to use a wireless router as an adjunct to my home network.
I would like to be able to have public network ip addresses assigned
from my dhcpd server that are in a different subnet from other the
machines in my home.  I thought this would be possible but apparently
not.  I could have the wireless router assign separate subnet ip
addresses but, then I would not be able to access the home subnet
machines with my wireless connected laptop.

Is there any way to be able to have two networks work off of one nic
card with dhcpd?

Greg

James A. Peltier

2017-Jan-16 04:12 UTC

head link

[CentOS] Centos 7 dhcpd failure to allow a 2nd network over same interal nic

VLANs are your friend, otherwise DHCPD is not going to understand how to
properly answer your request for different networks on the same interface.

----- On 14 Jan, 2017, at 11:59, Gregory P. Ennis PoMec at PoMec.net wrote:

| Everyone,
| 
| I am trying to set up a second internal network  (192.168.0.0/24) and
| have not been able to get dhcp to start when I have the following in my
| dhcpd.conf file :
| 
| subnet 192.168.0.0 netmask 255.255.255.0 {
|        range 192.168.0.110 192.168.0.130;
|        option subnet-mask 255.255.255.0;
|        option broadcast-address 192.168.0.255;
|        option routers 192.168.0.1;
|        option domain-name-servers 192.168.0.1;
| }
| 
| When i remove the above from dhcpd.conf dhcpd works perfectly
| 
| I have my internal nic card set with two ip addresses one of which is
| 192.168.0.1. the other address is my standard internal network address.
| 
| I have also set up the domain server to allow access from
| 192.168.0.0/24, and the firewall allows internal access to the same
| subnet.
| 
| The error that I get is the following :
| 
| Job for dhcpd.service failed because the control process exited with error
code.
| See "systemctl status dhcpd.service" and "journalctl -xe"
for details.
| 
| When I evaluate journalctl -xe the following is obtained :
| 
| dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
| dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
| dhcpd[18763]: All rights reserved.
| dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
| dhcpd[18763]: Not searching LDAP since ldap-server, ldap-port and
| ldap-base-dn were not specified in the config file
| dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
| dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
| dhcpd[18763]: All rights reserved.
| dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
| dhcpd[18763]: Wrote 0 deleted host decls to leases file.
| dhcpd[18763]: Wrote 0 new dynamic host decls to leases file.
| dhcpd[18763]: Wrote 2 leases to leases file.
| dhcpd[18763]: Interface enp0s29u1u2 matches multiple shared networks
| dhcpd[18763]:
| dhcpd[18763]: This version of ISC DHCP is based on the release available
| dhcpd[18763]: on ftp.isc.org.  Features have been added and other
| changes
| dhcpd[18763]: have been made to the base software release in order to
| make
| dhcpd[18763]: it work better with this distribution.
| dhcpd[18763]:
| dhcpd[18763]: Please report for this software via the CentOS Bugs
| Database:
| dhcpd[18763]:     http://bugs.centos.org/
| dhcpd.service: main process exited, code=exited, status=1/FAILURE
| dhcpd[18763]:
| systemd[1]: Failed to start DHCPv4 Server Daemon.
| 
| When I review the information about dhcpd it appears that it can manage
| the ip addresses for two networks on different nic cards, but is there a
| problem in having it manage two networks on the same nic card?
| 
| Does anyone have any ideas?  Would sure appreciate your help.
| 
| Greg Ennis
| 
| 
| 
| --
| Greg Ennis
| PoMec Corporation
| www.PoMec.Net
| 
| 
| _______________________________________________
| CentOS mailing list
| CentOS at centos.org
| https://lists.centos.org/mailman/listinfo/centos

-- 
James A. Peltier
IT Services - Research Computing Group
Simon Fraser University - Burnaby Campus
Phone   : 604-365-6432
Fax     : 778-782-3045
E-Mail  : jpeltier at sfu.ca
Website : http://www.sfu.ca/itservices
Twitter : @sfu_rcg
Powering Engagement Through Technology

Rob Kampen

2017-Jan-16 08:44 UTC

head link

[CentOS] Centos 7 dhcpd failure to allow a 2nd network over same interal nic

On 16/01/17 17:12, James A. Peltier wrote:> VLANs are your friend, otherwise DHCPD is not going to understand how to
properly answer your request for different networks on the same interface.
>
> ----- On 14 Jan, 2017, at 11:59, Gregory P. Ennis PoMec at PoMec.net wrote:
>
> | Everyone,
> |
> | I am trying to set up a second internal network  (192.168.0.0/24) and
> | have not been able to get dhcp to start when I have the following in my
> | dhcpd.conf file :
> |
> | subnet 192.168.0.0 netmask 255.255.255.0 {
> |        range 192.168.0.110 192.168.0.130;
> |        option subnet-mask 255.255.255.0;
> |        option broadcast-address 192.168.0.255;
> |        option routers 192.168.0.1;
> |        option domain-name-servers 192.168.0.1;
> | }
> |
> | When i remove the above from dhcpd.conf dhcpd works perfectly
> |
> | I have my internal nic card set with two ip addresses one of which is
> | 192.168.0.1. the other address is my standard internal network address.
> |
> | I have also set up the domain server to allow access from
> | 192.168.0.0/24, and the firewall allows internal access to the same
> | subnet.
> |
> | The error that I get is the following :
> |
> | Job for dhcpd.service failed because the control process exited with
error code.
> | See "systemctl status dhcpd.service" and "journalctl
-xe" for details.
> |
> | When I evaluate journalctl -xe the following is obtained :
> |
> | dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
> | dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
> | dhcpd[18763]: All rights reserved.
> | dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
> | dhcpd[18763]: Not searching LDAP since ldap-server, ldap-port and
> | ldap-base-dn were not specified in the config file
> | dhcpd[18763]: Internet Systems Consortium DHCP Server 4.2.5
> | dhcpd[18763]: Copyright 2004-2013 Internet Systems Consortium.
> | dhcpd[18763]: All rights reserved.
> | dhcpd[18763]: For info, please visit https://www.isc.org/software/dhcp/
> | dhcpd[18763]: Wrote 0 deleted host decls to leases file.
> | dhcpd[18763]: Wrote 0 new dynamic host decls to leases file.
> | dhcpd[18763]: Wrote 2 leases to leases file.
> | dhcpd[18763]: Interface enp0s29u1u2 matches multiple shared networks
> | dhcpd[18763]:
> | dhcpd[18763]: This version of ISC DHCP is based on the release available
> | dhcpd[18763]: on ftp.isc.org.  Features have been added and other
> | changes
> | dhcpd[18763]: have been made to the base software release in order to
> | make
> | dhcpd[18763]: it work better with this distribution.
> | dhcpd[18763]:
> | dhcpd[18763]: Please report for this software via the CentOS Bugs
> | Database:
> | dhcpd[18763]:     http://bugs.centos.org/
> | dhcpd.service: main process exited, code=exited, status=1/FAILURE
> | dhcpd[18763]:
> | systemd[1]: Failed to start DHCPv4 Server Daemon.
> |
> | When I review the information about dhcpd it appears that it can manage
> | the ip addresses for two networks on different nic cards, but is there a
> | problem in having it manage two networks on the same nic card?
> |
> | Does anyone have any ideas?  Would sure appreciate your help.
> |
> | Greg Ennis
> |
> |
> |
> | --
> | Greg Ennis
> | PoMec Corporation
> | www.PoMec.Net
> |
> |
> | _______________________________________________
> | CentOS mailing list
> | CentOS at centos.org
> | https://lists.centos.org/mailman/listinfo/centos
>Here's an idea - untested.
set up a network on the single nic - say 192.168.55.xx/24
set up the dhcp to offer leases from a subset of this network - say 
192.168.55.128/28
set up fixed leases based upon mac address from the remainder of the 
network - i.e. outside the subset above - e.g. 192.168.55.1/28
then route / firewall as required - i.e. trusted known mac address hence 
IP address allowed vs unknown guest given an IP address we can block or 
otherwise handle.
As indicated, this is not tested but if memory serves, dhcpd will allow 
this kind of allocation.
HTH
Rob

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