The DM200 routing table shows what the problem is:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Ifac
default 172.16.18.16 0.0.0.0 UG 0 0 0 ppp0
172.16.18.16 * 255.255.255.255 UH 0 0 0 ppp0
192.0.0.0 * 255.0.0.0 U 0 0 0 br0
This (bridge) entry is in error:
192.0.0.0 * 255.0.0.0 U 0 0 0 br0
Observed in latest and preceding frimware v1.0.0.52 and v1.0.0.44 respectively.
I have two new DM200's just installed and both suffer this same issue.
See: tools.ietf.org/html/rfc5735
>>Special Use IPv4 Addresses<<
192.0.0.0/24 IETF Protocol Assignments RFC 5736
192.0.2.0/24 TEST-NET-1 RFC 5737
192.88.99.0/24 6to4 Relay Anycast RFC 3068
192.168.0.0/16 Private-Use Networks RFC 1918
192.0.0.0/24 - This block is reserved for IETF protocol assignments.
At the time of writing this document, there are no current
assignments. Allocation policy for future assignments is given in
[RFC5736].
192.0.2.0/24 - This block is assigned as "TEST-NET-1" for use in
documentation and example code. It is often used in conjunction with
domain names example.com or example.net in vendor and protocol
documentation. As described in [RFC5737], addresses within this
block do not legitimately appear on the public Internet and can be
used without any coordination with IANA or an Internet registry. See
[RFC1166].
192.88.99.0/24 - This block is allocated for use as 6to4 relay
anycast addresses, in [RFC3068]. In contrast with previously
described blocks, packets destined to addresses from this block do
appear in the public Internet. [RFC3068], Section 7, describes
operational practices to prevent the malicious use of this block in
routing protocols.
192.168.0.0/16 - This block is set aside for use in private networks.
Its intended use is documented in [RFC1918]. As described in that
RFC, addresses within this block do not legitimately appear on the
public Internet. These addresses can be used without any
coordination with IANA or an Internet registry.
eod.
