Ubuntu: dhcp server on NIC with 2 (or more) ip address












0















On Ubuntu 18.04, I have my eth1 configured with 2 static ip:



$ ip addr show eth1
8: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:80:c8:3d:19:94 brd ff:ff:ff:ff:ff:ff
inet 169.254.123.52/16 brd 169.254.255.255 scope link noprefixroute eth1
valid_lft forever preferred_lft forever
inet 192.168.55.1/24 brd 192.168.55.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever


On eth1 I have configured the dhcp server:



option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

#local-address 192.168.55.1
subnet 192.168.55.0 netmask 255.255.255.0 {
range 192.168.55.100 192.168.55.150;
}


when a client asks for an ip address, however, the packets arrive with ip source in the wrong subnet:



wireshark screenshot



Note that packets from the dhcp server have ip source 169.254.xxx.yyy but assign ip in the subnet 192.168.55.zzz



Is that a problem? How do I make sure that packages are generated with the ip in the right subnet? Is this a linux or dhcp server setting?










share|improve this question























  • Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

    – Gert Jan Kraaijeveld
    Jan 28 at 20:00











  • @Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

    – mastupristi
    Jan 29 at 21:59
















0















On Ubuntu 18.04, I have my eth1 configured with 2 static ip:



$ ip addr show eth1
8: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:80:c8:3d:19:94 brd ff:ff:ff:ff:ff:ff
inet 169.254.123.52/16 brd 169.254.255.255 scope link noprefixroute eth1
valid_lft forever preferred_lft forever
inet 192.168.55.1/24 brd 192.168.55.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever


On eth1 I have configured the dhcp server:



option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

#local-address 192.168.55.1
subnet 192.168.55.0 netmask 255.255.255.0 {
range 192.168.55.100 192.168.55.150;
}


when a client asks for an ip address, however, the packets arrive with ip source in the wrong subnet:



wireshark screenshot



Note that packets from the dhcp server have ip source 169.254.xxx.yyy but assign ip in the subnet 192.168.55.zzz



Is that a problem? How do I make sure that packages are generated with the ip in the right subnet? Is this a linux or dhcp server setting?










share|improve this question























  • Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

    – Gert Jan Kraaijeveld
    Jan 28 at 20:00











  • @Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

    – mastupristi
    Jan 29 at 21:59














0












0








0








On Ubuntu 18.04, I have my eth1 configured with 2 static ip:



$ ip addr show eth1
8: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:80:c8:3d:19:94 brd ff:ff:ff:ff:ff:ff
inet 169.254.123.52/16 brd 169.254.255.255 scope link noprefixroute eth1
valid_lft forever preferred_lft forever
inet 192.168.55.1/24 brd 192.168.55.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever


On eth1 I have configured the dhcp server:



option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

#local-address 192.168.55.1
subnet 192.168.55.0 netmask 255.255.255.0 {
range 192.168.55.100 192.168.55.150;
}


when a client asks for an ip address, however, the packets arrive with ip source in the wrong subnet:



wireshark screenshot



Note that packets from the dhcp server have ip source 169.254.xxx.yyy but assign ip in the subnet 192.168.55.zzz



Is that a problem? How do I make sure that packages are generated with the ip in the right subnet? Is this a linux or dhcp server setting?










share|improve this question














On Ubuntu 18.04, I have my eth1 configured with 2 static ip:



$ ip addr show eth1
8: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:80:c8:3d:19:94 brd ff:ff:ff:ff:ff:ff
inet 169.254.123.52/16 brd 169.254.255.255 scope link noprefixroute eth1
valid_lft forever preferred_lft forever
inet 192.168.55.1/24 brd 192.168.55.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever


On eth1 I have configured the dhcp server:



option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

#local-address 192.168.55.1
subnet 192.168.55.0 netmask 255.255.255.0 {
range 192.168.55.100 192.168.55.150;
}


when a client asks for an ip address, however, the packets arrive with ip source in the wrong subnet:



wireshark screenshot



Note that packets from the dhcp server have ip source 169.254.xxx.yyy but assign ip in the subnet 192.168.55.zzz



Is that a problem? How do I make sure that packages are generated with the ip in the right subnet? Is this a linux or dhcp server setting?







linux networking dhcp ubuntu-18.04 dhcp-server






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Jan 28 at 13:59









mastupristimastupristi

11




11













  • Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

    – Gert Jan Kraaijeveld
    Jan 28 at 20:00











  • @Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

    – mastupristi
    Jan 29 at 21:59



















  • Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

    – Gert Jan Kraaijeveld
    Jan 28 at 20:00











  • @Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

    – mastupristi
    Jan 29 at 21:59

















Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

– Gert Jan Kraaijeveld
Jan 28 at 20:00





Why do you have an APIPA address(169.254.0.0/16) statically bound to the NIC? What happens when you remove that binding?

– Gert Jan Kraaijeveld
Jan 28 at 20:00













@Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

– mastupristi
Jan 29 at 21:59





@Gert Jan Kraaijeveld I use an APIPA address for needs related to my work. The problem would be the same if I had configured an address in the subnet 10.0.0.xxx/24. The dhcp server would generate packets from an address in the subnet 10.0.0.xxx/24 to assign an address in the subnet 192.168.55.yyy/24.

– mastupristi
Jan 29 at 21:59










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