systemd.networkd: DHCP and link-local address
Is it possible to configure systemd-networkd in a way like on Windows i nterms of DHCP and link-local address?
I mean:
- if address can be obtained from DHCP, then fine - we are done.
- if getting address from DHCP fails, then backfall to 169.254.x.x.
Also similar to RFC3927.
I am bit surprised how LinkLocalAddressing= option works. It just overrides DHCP. With settings like:
[Match]
Name=eth0
KernelCommandLine=!nfsroot
[Network]
DHCP=ipv4
LinkLocalAddressing=yes
I get:
Dec 17 15:10:43 my-system systemd-networkd[1276]: eth0: IPv6 successfully enabled
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: Gained carrier
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: DHCPv4 address 10.114.138.133/24 via 10.114.138.1
Dec 17 15:10:45 my-system systemd-networkd[1276]: eth0: Gained IPv6LL
Dec 17 15:10:57 my-system systemd-networkd[1276]: eth0: Configured
root@my-system:~#
root@my-system:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:44:44:00:04:17
inet addr:169.254.184.36 Bcast:169.254.255.255
Mask:255.255.0.0
networking systemd systemd-networkd
asked Dec 17 at 16:18
coulomb
62
add a comment |
Is it possible to configure systemd-networkd in a way like on Windows i nterms of DHCP and link-local address?
I mean:
- if address can be obtained from DHCP, then fine - we are done.
- if getting address from DHCP fails, then backfall to 169.254.x.x.
Also similar to RFC3927.
I am bit surprised how LinkLocalAddressing= option works. It just overrides DHCP. With settings like:
[Match]
Name=eth0
KernelCommandLine=!nfsroot
[Network]
DHCP=ipv4
LinkLocalAddressing=yes
I get:
Dec 17 15:10:43 my-system systemd-networkd[1276]: eth0: IPv6 successfully enabled
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: Gained carrier
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: DHCPv4 address 10.114.138.133/24 via 10.114.138.1
Dec 17 15:10:45 my-system systemd-networkd[1276]: eth0: Gained IPv6LL
Dec 17 15:10:57 my-system systemd-networkd[1276]: eth0: Configured
root@my-system:~#
root@my-system:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:44:44:00:04:17
inet addr:169.254.184.36 Bcast:169.254.255.255
Mask:255.255.0.0
networking systemd systemd-networkd
asked Dec 17 at 16:18
coulomb
62
Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37
add a comment |
Is it possible to configure systemd-networkd in a way like on Windows i nterms of DHCP and link-local address?
I mean:
- if address can be obtained from DHCP, then fine - we are done.
- if getting address from DHCP fails, then backfall to 169.254.x.x.
Also similar to RFC3927.
I am bit surprised how LinkLocalAddressing= option works. It just overrides DHCP. With settings like:
[Match]
Name=eth0
KernelCommandLine=!nfsroot
[Network]
DHCP=ipv4
LinkLocalAddressing=yes
I get:
Dec 17 15:10:43 my-system systemd-networkd[1276]: eth0: IPv6 successfully enabled
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: Gained carrier
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: DHCPv4 address 10.114.138.133/24 via 10.114.138.1
Dec 17 15:10:45 my-system systemd-networkd[1276]: eth0: Gained IPv6LL
Dec 17 15:10:57 my-system systemd-networkd[1276]: eth0: Configured
root@my-system:~#
root@my-system:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:44:44:00:04:17
inet addr:169.254.184.36 Bcast:169.254.255.255
Mask:255.255.0.0
networking systemd systemd-networkd
asked Dec 17 at 16:18
coulomb
62
Is it possible to configure systemd-networkd in a way like on Windows i nterms of DHCP and link-local address?
I mean:
- if address can be obtained from DHCP, then fine - we are done.
- if getting address from DHCP fails, then backfall to 169.254.x.x.
Also similar to RFC3927.
I am bit surprised how LinkLocalAddressing= option works. It just overrides DHCP. With settings like:
[Match]
Name=eth0
KernelCommandLine=!nfsroot
[Network]
DHCP=ipv4
LinkLocalAddressing=yes
I get:
Dec 17 15:10:43 my-system systemd-networkd[1276]: eth0: IPv6 successfully enabled
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: Gained carrier
Dec 17 15:10:44 my-system systemd-networkd[1276]: eth0: DHCPv4 address 10.114.138.133/24 via 10.114.138.1
Dec 17 15:10:45 my-system systemd-networkd[1276]: eth0: Gained IPv6LL
Dec 17 15:10:57 my-system systemd-networkd[1276]: eth0: Configured
root@my-system:~#
root@my-system:~# ifconfig
eth0 Link encap:Ethernet HWaddr 00:44:44:00:04:17
inet addr:169.254.184.36 Bcast:169.254.255.255
Mask:255.255.0.0
networking systemd systemd-networkd
networking systemd systemd-networkd
asked Dec 17 at 16:18
coulomb
62
asked Dec 17 at 16:18
coulomb
62
asked Dec 17 at 16:18
coulomb
62
asked Dec 17 at 16:18
coulomb
62
asked Dec 17 at 16:18
coulomb
62
62
Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37
add a comment |
Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37
Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37
Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37
add a comment |
1 Answer
1
active
oldest
votes
Try using "ip addr show" rather than ifconfig. I suspect that this will show you two IP addresses:
- the link local address; and
- the DHCP assigned IP address.
systemd-networkd is not "overriding" the DHCP assigned address with the link local address. Both addresses are active and working. It's just that ifconfig is only capable of showing a single IP address on the interface and it shows you the first address that it sees, ignoring any others.
ifconfig is already deprecated. It's time to switch to using the ip utility instead... Here's a cheat sheet that might help:
https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf
answered Dec 17 at 17:58
the_kid
1
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
add a comment |
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1 Answer
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1 Answer
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active
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Try using "ip addr show" rather than ifconfig. I suspect that this will show you two IP addresses:
- the link local address; and
- the DHCP assigned IP address.
systemd-networkd is not "overriding" the DHCP assigned address with the link local address. Both addresses are active and working. It's just that ifconfig is only capable of showing a single IP address on the interface and it shows you the first address that it sees, ignoring any others.
ifconfig is already deprecated. It's time to switch to using the ip utility instead... Here's a cheat sheet that might help:
https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf
answered Dec 17 at 17:58
the_kid
1
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
add a comment |
Try using "ip addr show" rather than ifconfig. I suspect that this will show you two IP addresses:
- the link local address; and
- the DHCP assigned IP address.
systemd-networkd is not "overriding" the DHCP assigned address with the link local address. Both addresses are active and working. It's just that ifconfig is only capable of showing a single IP address on the interface and it shows you the first address that it sees, ignoring any others.
ifconfig is already deprecated. It's time to switch to using the ip utility instead... Here's a cheat sheet that might help:
https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf
answered Dec 17 at 17:58
the_kid
1
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
add a comment |
Try using "ip addr show" rather than ifconfig. I suspect that this will show you two IP addresses:
- the link local address; and
- the DHCP assigned IP address.
systemd-networkd is not "overriding" the DHCP assigned address with the link local address. Both addresses are active and working. It's just that ifconfig is only capable of showing a single IP address on the interface and it shows you the first address that it sees, ignoring any others.
ifconfig is already deprecated. It's time to switch to using the ip utility instead... Here's a cheat sheet that might help:
https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf
answered Dec 17 at 17:58
the_kid
1
Try using "ip addr show" rather than ifconfig. I suspect that this will show you two IP addresses:
- the link local address; and
- the DHCP assigned IP address.
systemd-networkd is not "overriding" the DHCP assigned address with the link local address. Both addresses are active and working. It's just that ifconfig is only capable of showing a single IP address on the interface and it shows you the first address that it sees, ignoring any others.
ifconfig is already deprecated. It's time to switch to using the ip utility instead... Here's a cheat sheet that might help:
https://access.redhat.com/sites/default/files/attachments/rh_ip_command_cheatsheet_1214_jcs_print.pdf
answered Dec 17 at 17:58
the_kid
1
answered Dec 17 at 17:58
the_kid
1
answered Dec 17 at 17:58
the_kid
1
answered Dec 17 at 17:58
the_kid
1
1
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
add a comment |
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
You are right - both addresses are active and shown by 'ip a'
– coulomb
Dec 19 at 13:26
add a comment |
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Is not that the default behaviour?
– Rui F Ribeiro
Dec 17 at 16:37