dhcpd offer ip to it's own interface?

dhcpd offer ip to it's own interface?

Post by Peter Pe » Sat, 06 Oct 2001 12:22:34



my dhcpd server keep offering ip to it's own interface after a specific time.
and network down...any solution to solve it?
my box connect to the internet thru eth0 -> cable modem(dhcp)
and ipalias eth0:0-9 192.168.0.1-9 for local network
system redhat 7.1
adding another network card eth1 and running dhcpd on it should solve the
problem, but I hope cheapest solution:) thanks!

--after dhcpd offer ip to it's own interface, network down...
route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0 eth0

---before good---
route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
63.18.64.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0 eth0

/var/log/messages
Oct  5 dhcpd: Internet Software Consortium DHCP Server 2.0pl5
Oct  5 dhcpd: Copyright 1995, 1996, 1997, 1998, 1999 The Interne
Oct  5 dhcpd: All rights reserved.
Oct  5 dhcpd:
Oct  5 dhcpd: Please contribute if you find this software useful
Oct  5 dhcpd: For info, please visit http://www.isc.org/dhcp-con
Oct  5 dhcpd:
Oct  5 dhcpd: Interface eth0 matches multiple shared networks
Oct  5 dhcpd: Listening on Socket/eth0/192.168.0.0
Oct  5 dhcpd: Sending on   Socket/eth0/192.168.0.0
Oct  5 dhcpd: dhcpd startup succeeded

Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPREQUEST for 63.18.67.247 from 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPNAK on 63.18.67.247 to 00:10:ca:4b:6c:46 via eth0
Oct  5 dhcpd: DHCPREQUEST for 192.168.0.129 from 00:80:c8:f7:86:83 via eth0
Oct  5 dhcpd: DHCPACK on 192.168.0.129 to 00:80:c8:f7:86:83 via eth0
Oct  5 kernel: eth0: using NWAY device table, not 8

/var/lib/dhcp/dhcpd.leases
lease 192.168.0.128 {
        starts 5 2001/10/05 01:13:54;
        ends 5 2001/10/05 01:15:54;
        hardware ethernet 00:10:ca:4b:6c:46;
        client-hostname "abc.com";

Quote:}

/etc/dhcpd.conf
not authoritative;
subnet 63.18.64.0 netmask 255.255.252.0 {
not authoritative;
Quote:}

subnet 192.168.0.0 netmask 255.255.255.0 {
authoritative;
        option routers                  192.168.0.1;
        option subnet-mask              255.255.255.0;
        option broadcast-address        192.168.0.255;
        option domain-name-servers      212.167.240.221;
        range 192.168.0.128 192.168.0.255;
        default-lease-time 21600;
        max-lease-time 43200;
Quote:}

 
 
 

dhcpd offer ip to it's own interface?

Post by Michael F » Sat, 06 Oct 2001 15:04:52


Personally, I'd always use a 2nd card... and 2nd hand cards are cheap
anyways..

>my dhcpd server keep offering ip to it's own interface after a specific time.
>and network down...any solution to solve it?
>my box connect to the internet thru eth0 -> cable modem(dhcp)
>and ipalias eth0:0-9 192.168.0.1-9 for local network
>system redhat 7.1
>adding another network card eth1 and running dhcpd on it should solve the
>problem, but I hope cheapest solution:) thanks!

>--after dhcpd offer ip to it's own interface, network down...
>route -n
>Kernel IP routing table
>Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
>192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
>0.0.0.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
>127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
>0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0 eth0

>---before good---
>route -n
>Kernel IP routing table
>Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
>192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
>63.18.64.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
>127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
>0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0 eth0

>/var/log/messages
>Oct  5 dhcpd: Internet Software Consortium DHCP Server 2.0pl5
>Oct  5 dhcpd: Copyright 1995, 1996, 1997, 1998, 1999 The Interne
>Oct  5 dhcpd: All rights reserved.
>Oct  5 dhcpd:
>Oct  5 dhcpd: Please contribute if you find this software useful
>Oct  5 dhcpd: For info, please visit http://www.isc.org/dhcp-con
>Oct  5 dhcpd:
>Oct  5 dhcpd: Interface eth0 matches multiple shared networks
>Oct  5 dhcpd: Listening on Socket/eth0/192.168.0.0
>Oct  5 dhcpd: Sending on   Socket/eth0/192.168.0.0
>Oct  5 dhcpd: dhcpd startup succeeded

>Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPREQUEST for 63.18.67.247 from 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPNAK on 63.18.67.247 to 00:10:ca:4b:6c:46 via eth0
>Oct  5 dhcpd: DHCPREQUEST for 192.168.0.129 from 00:80:c8:f7:86:83 via eth0
>Oct  5 dhcpd: DHCPACK on 192.168.0.129 to 00:80:c8:f7:86:83 via eth0
>Oct  5 kernel: eth0: using NWAY device table, not 8

>/var/lib/dhcp/dhcpd.leases
>lease 192.168.0.128 {
>        starts 5 2001/10/05 01:13:54;
>        ends 5 2001/10/05 01:15:54;
>        hardware ethernet 00:10:ca:4b:6c:46;
>        client-hostname "abc.com";
>}

>/etc/dhcpd.conf
>not authoritative;
>subnet 63.18.64.0 netmask 255.255.252.0 {
>not authoritative;
>}
>subnet 192.168.0.0 netmask 255.255.255.0 {
>authoritative;
>        option routers                  192.168.0.1;
>        option subnet-mask              255.255.255.0;
>        option broadcast-address        192.168.0.255;
>        option domain-name-servers      212.167.240.221;
>        range 192.168.0.128 192.168.0.255;
>        default-lease-time 21600;
>        max-lease-time 43200;
>}


 
 
 

dhcpd offer ip to it's own interface?

Post by Chase Casanov » Sun, 07 Oct 2001 07:23:35


Hi,

When you start running dhcpd on the same interface that is connected to your
modem your service provider will probably shut your network access down.
Most service providers have safeguards against having dhcp servers running
on there network.  Because what you end up doing is putting another dhcp
server on their network and YOUR computer starts responding to the requests
being put out by the service provider's customers, at least that is what
would happen if they didn't have safeguards against that.

Also you can't run dhcpd with an address range that is outside that of the
ethernet card that you are trying to run dhcpd from, so this may be another
reason why you are having problems.

Simple solution: Buy another NIC and use it for dhcpd

Good Luck,
C3


Quote:> my dhcpd server keep offering ip to it's own interface after a specific
time.
> and network down...any solution to solve it?
> my box connect to the internet thru eth0 -> cable modem(dhcp)
> and ipalias eth0:0-9 192.168.0.1-9 for local network
> system redhat 7.1
> adding another network card eth1 and running dhcpd on it should solve the
> problem, but I hope cheapest solution:) thanks!

> --after dhcpd offer ip to it's own interface, network down...
> route -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
> 192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0
eth0
> 0.0.0.0      0.0.0.0         255.255.252.0   U     0      0        0 eth0
> 127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
> 0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0
eth0

> ---before good---
> route -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use
Iface
> 192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0
eth0
> 63.18.64.0      0.0.0.0         255.255.252.0   U     0      0        0
eth0
> 127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
> 0.0.0.0         63.18.64.1      0.0.0.0         UG    0      0        0
eth0

> /var/log/messages
> Oct  5 dhcpd: Internet Software Consortium DHCP Server 2.0pl5
> Oct  5 dhcpd: Copyright 1995, 1996, 1997, 1998, 1999 The Interne
> Oct  5 dhcpd: All rights reserved.
> Oct  5 dhcpd:
> Oct  5 dhcpd: Please contribute if you find this software useful
> Oct  5 dhcpd: For info, please visit http://www.isc.org/dhcp-con
> Oct  5 dhcpd:
> Oct  5 dhcpd: Interface eth0 matches multiple shared networks
> Oct  5 dhcpd: Listening on Socket/eth0/192.168.0.0
> Oct  5 dhcpd: Sending on   Socket/eth0/192.168.0.0
> Oct  5 dhcpd: dhcpd startup succeeded

> Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPDISCOVER from 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPOFFER on 192.168.0.128 to 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPREQUEST for 63.18.67.247 from 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPNAK on 63.18.67.247 to 00:10:ca:4b:6c:46 via eth0
> Oct  5 dhcpd: DHCPREQUEST for 192.168.0.129 from 00:80:c8:f7:86:83 via
eth0
> Oct  5 dhcpd: DHCPACK on 192.168.0.129 to 00:80:c8:f7:86:83 via eth0
> Oct  5 kernel: eth0: using NWAY device table, not 8

> /var/lib/dhcp/dhcpd.leases
> lease 192.168.0.128 {
>         starts 5 2001/10/05 01:13:54;
>         ends 5 2001/10/05 01:15:54;
>         hardware ethernet 00:10:ca:4b:6c:46;
>         client-hostname "abc.com";
> }

> /etc/dhcpd.conf
> not authoritative;
> subnet 63.18.64.0 netmask 255.255.252.0 {
> not authoritative;
> }
> subnet 192.168.0.0 netmask 255.255.255.0 {
> authoritative;
>         option routers                  192.168.0.1;
>         option subnet-mask              255.255.255.0;
>         option broadcast-address        192.168.0.255;
>         option domain-name-servers      212.167.240.221;
>         range 192.168.0.128 192.168.0.255;
>         default-lease-time 21600;
>         max-lease-time 43200;
> }