bad ip assignment configuration meraki

Meraki MX Device getting Bad IP Assignment Configuration

I just replaced the ISP at an outer office. The new ISP plugged in their routers for phone/Internet. The Internet cable went into you MX64 device and started dishing out Internet and Network connectivity.

When I went to check on the device online, I noticed the Bad IP Assignment Configuration message. Device is still working properly, dishing out the correct IP addresses for that office, serving up the MR33 SSID. I’m able to access the Internet and all networked files, I’m just not understanding why the Bad IP Assignment Configuration is showing up.

I’ve read through Meraki’s information and sort of understand it… the device is not receiving an ARP reply from the gateway… even though I have entered that information in statically. Why can’t the device reach the “default gateway” I had setup for it with the previous ISP? What changed other than maybe the IP address that the new ISP is giving out? Am I on the right track in thinking it’s related to the new ISP?

Did the device turn off? Maybe a bad ARP table? Did you reboot it to see if that helps? Also if any switch or device in between.

Can you PING the gateway from it?

When the technician finished the install and hooked up the Internet cable, he rebooted each device. The MX64, the MS220 and the MR33 were rebooted and came back up functioning properly.

Pinging doesn’t seem to be an issue (from the MX64 tools tab).

Currently the device is getting the following IP information:

General PUBLIC IP - 198.37.249.173

DHCP - Static IP

STATUS - Active

IP (DHCP) - 192.168.0.3

GATEWAY - 192.168.0.1 DNS - 209.18.47.61, 209.18.47.62

The General Public IP is the IP that the ISP is handing out (I assume). The WAN information doesn’t jive with the rest of my network, however. Instead of 192.168.0.1, I had it as 192.168.3.1. I cannot adjust the settings to my former configuration. The DNS settings ar completely off as well.

What is your internal network? 192.168.3.X?

Are u onsite? I woild remove the dhcp and hard code it. See what happens.

That’s the internal network for that office, yes. I am not onsite. DHCP is removed. It is set statically but the settings will not take effect. I get the impression something is keeping it from taking effect, like the ISP router. The ISP mentioned putting the router into Bridge Mode so that the devices on my network (the MX) could dish out IP Addresses? Maybe that is the solution?

Something is wrong. You need to reconfigure that device. There is something in the middle or those networks could not talk. I bet the internal network changed… to 192.168.3.X and are getting DHCP from the same thing the Meraki is

Did you set the gateway on the WAN side? That’s only set at the wired.meraki.com address for static ISPs.

We’ve just started experiencing this after an internet outage in our building. Everything appears to be working but we’ve now got this Bad IP Configuration error. Nothing has changed our side.

Asked the ISP to clear the ARP Table, hopefully this will resolve it,

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Internal: Multicast Handbook

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This handbook aims to provide a quick preview of multicast and guidance on troubleshooting issues relating to Layer 2 and Layer 3 multicast. Multiple sections in the handbook will reference other detailed documents with in-depth knowledge of multicast.

Terms to know

• Multicast Source: A device or application transmitting multicast traffic. 
• Group:   An IP address from range 224.0.0.0 to 239.255.255.255 is commonly referred to as a multicast IP or multicast group because it identifies a group of devices interested in receiving a multicast stream. 

Source 10.0.200.2 transmitting multicast stream to group 239.1.8.27

• Multicast Receiver: A device that is interested in receiving multicast traffic. 
• Joins: A receiver (host) sends an IGMP Membership Report to the IGMP querier to indicate that it wants to be or is a member of a given group.

Receiver 10.101.140.72 sending IGMP Join for group 239.255.255.250

• IGMP querier and Query: IGMP querier (router or switch) periodically sends a Query to the local subnet to check for the existence of multicast group members.

Example for IGMP Query packets

Switch with this configuration will act as a querier for VLAN 128 using source IP 192.168.128.12

• Protocol Independent Multicast (PIM): There are four working modes of PIM. The Meraki switch platform only supports PIM-SM (Sparse Mode). In PIM-SM, traffic is not forwarded on a segment unless an explicit request originates from the network segment. 
• Multicast router: A router or L3 switch routing multicast traffic for a specific VLAN.  

This switch will route multicast traffic for VLAN 10 (and send Query/PIM using IP 192.168.150.1)

• Rendezvous Point (RP): A multicast router acting as the RP receives multicast streams from the source and IGMP/PIM Joins (or Leaves) from the receiver. The RP is in charge of allowing multicast streams to the receiver. The RP's role becomes essential when dealing with multiple L3 segments between the source and the receiver. When a single PIM router is present, it's multicast routing on a stick where the RP points to itself.

How does multicast work?

Pre-checks for multicast to function.

The source must send traffic to a multicast group. The receiver must join the target multicast group to receive multicast as a member. 

The network should have an  appropriate  multicast  querier for L2 multicast .

 For  L3 multicast , the switches should have multicast routing enabled for appropriate VLANs and a Rendezvous Point (RP).  

IGMP Snooping should be enabled . Flood Unknown Multicast should be preferably disabled. ( Scenarios  )

The multicast stream from the source and the IGMP Join from the receiver should reach the IGMP querier / multicast router. 

For this, the switches along the path should build appropriate forwarding tables based on snooped IGMP messages (and, if applicable, routing information using IGMP and PIM).  

How does a switch handle multicast traffic?

An L2 switch will forward an IGMP Membership Query to all ports in the same VLAN except the receiving port.

L2 switches forward IGMP Join/Leave on the port where it sees an IGMP Membership Query for the same VLAN. 

A L2 switch only sends ingressing multicast streams to any other port where it sees an IGMP Join or a Membership Query for the appropriate VLAN. The switch will flood incoming multicast streams to all other ports if "Flood unknown multicast traffic" is enabled and the multicast group is unknown (no active members have joined). 

L3 switches (that are not the RP) would encapsulate part of the multicast stream from the source in a PIM Register message and forward it to the RP. 

Similarly, L3 switches generate and send a PIM Join toward the RP in response to an IGMP Join from the receiver. 

In L3 multicast, the RP will only allow the multicast traffic from the sender to the receiver if it has seen a Join (IGMP Join or PIM Join) from an interested receiver.  

If not, it will reject the PIM Register message with a PIM Register-Stop and temporarily suppress the source switch/router from trying to send the multicast traffic to the RP. 

Note that the RP allows multicast traffic from the source to the receiver by sending a PIM Join to the source. This PIM Join allows the source multicast router to send multicast traffic without encapsulating the stream. During this, the RP also sends a PIM Register-Stop to stop the PIM Registers from the source multicast router. 

PIM relies on the unicast routing table when determining where to send the PIM Joins/Prunes and Registers/Register-Stops.

How to troubleshoot a multicast problem?

L2 multicast troubleshooting:

Please refer to this KB article for more information on L2 multicast troubleshooting and relevant click handlers. IOS commands are here . 

L3 multicast troubleshooting: 

Do you see PIM Prune?

In PIM-SM, there are two types of designated routers (DRs) to consider:

The receiver DR sends PIM Join/Prune messages from the receiver toward the RP.

The source DR sends PIM Register messages from the source to the RP.

What does a PIM Prune look like? 

    Switch 10.7.253.45 is sending PIM Prune for client 10.44.255.35 for the group 238.1.8.27

We can see PIM Prunes from the receiver DR to the RP for one of two reasons: 

An IGMP Leave message from the receiver can trigger PIM Prune. 

In an L3 multicast topology, once multicast traffic begins flowing through the RP and the receiver DR (Rendezvous Point Tree or RPT), the receiver DR learns the source IP of the multicast stream. 

If a direct path exists between the receiver and the source, the receiver DR will switch to this path by sending PIM Joins directly towards the source. 

At this point, if this path does not go through the RP, the receiver DR will also send PIM Prune to the RP. Multicast traffic will now flow directly from the source to the receiver via this direct path (Source Path Tree or SPT). Please note that the RP will also send a corresponding PIM Prune for this receiver to the source DR to prevent any unnecessary duplicate traffic.

How to troubleshoot PIM Prune? 

If the PIM Prune is due to the receiver sending IGMP Leave, multicast will not work. 

If the PIM Prune is due to SPT, troubleshoot the multicast stream along the direct path between the source and the receiver.

Identify at which switch the traffic is breaking and verify configurations per the above flowchart.

Things to keep in mind: 

General: 

Please refer to the note here discussing a known caveat about 224.0.0.0/24 and the x.0.0.x or x.128.0.x addresses being treated as broadcast and never routed. 

IGMP querier election ensures only one device becomes the active querier. The router/switch with the lowest IP address becomes the active querier.

MS switches do not do Auto-RP and will need an RP configuration on the dashboard.   

Classic MS: 

Only the Active switch populates data under the /click/igmp_table/X handlers.

Multicast mactable entry for an aggregate port does not show AGGR/n as the port, like we now do for unicast entries. Instead, the entry lists the physical ports in the aggregate that are presently in a LACP-forwarding state.

For multicast mactable entries, the stacking ports are always in the mactable entry. If a stack member has a multicast entry where the learned port is from a different stack member, this remote port is not included in the entry. Instead, it's covered by the fact that the stacking ports are part of the entry.

Switch with MAC a8:46:9d:d5:43:31 will always have stack ports in mactable for multicast group 01:00:5E:

IGMP Querier is enabled on all VLANs by default for an MS390/C9300.

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