Default route not installed but received in dhcp offer

[Tom Eichhorn]

Hi,

I am booting the ubuntu cloud image for wily (from 27-Nov-2015 22:04) in an openstack enviroment. The system comes up,
gets an IP via DHCP, but no default route is being installed. A verification with dhcpdump shows that open 3, routers contains 1 entry.

Attached are screenshots from an ifup and from the dhcpdump, if any further input is required please let me know.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: isc-dhcp-client 4.3.1-5ubuntu3
ProcVersionSignature: Ubuntu 4.2.0-18.22-generic 4.2.3
Uname: Linux 4.2.0-18-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Tue Dec 1 12:44:14 2015
DhclientLeases:

Ec2AMI: ami-00000009
Ec2AMIManifest: FIXME
Ec2AvailabilityZone: nova
Ec2InstanceType: m1.small
Ec2Kernel: None
Ec2Ramdisk: None
ExecutablePath: /sbin/dhclient
ProcAttrCurrent: /sbin/dhclient (enforce)
ProcEnviron: PATH=(custom, no user)
SourcePackage: isc-dhcp
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dr. Jens Harbott (j-harbott)]

This is the expected behaviour if your DHCP server also specifies a classless static route, see RFC 3442:

If the DHCP server returns both a Classless Static Routes option and a Router option, the DHCP client MUST ignore the Router option.