> Source: [sk170922](https://support.checkpoint.com/results/sk/sk170922)

# sk170922 - Multicast packet drop at the beginning of a connection

| Property | Value |
|----------|-------|
| Solution ID | sk170922 |
| Date Created | 2020-12-09 |
| Last Modified | 2021-11-30 |
| Technical Level | General |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- * The following Multicast packet drop is seen in SmartConsole log:   
  `
  IP multicast routing failed (too many packets received before route was resolved)`

  <br />

  [![](https://sc1.checkpoint.com/sc/SolutionsStatics/sk170922/Drop-Detailed202012170943351.png)](https://sc1.checkpoint.com/sc/SolutionsStatics/sk170922/Drop-Detailed202012170943351.png "Click the image to see it in full size in a new tab/window")
* The rule base configured with Multicast Dynamic Routing, for example PIM (dense or spare mode).

* The output of the command: *"ipsctl -a net:dev:adp:mcrt:stats:hold_queue_full"* , is not '0'.


  **Important Note: The solution below does not apply and should not be attempted if the hold_queue_full value is 0.**

* Some multicast packets flow for the problematic multicast source IP and group.

## Cause

Various multicast feeds coming into Check Point Security Gateway with the same (S,G) (Multicast source, Multicast Group) entry.

## Solution

This problem was fixed. The fix is included in:

* [Jumbo Hotfix Accumulator for R80.40](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk165456) starting from Take 53
* [Jumbo Hotfix Accumulator for R80.30](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk153152) starting from Take 215
* [Jumbo Hotfix Accumulator for R80.20](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk137592) starting from Take 173

If you choose not to upgrade, Check Point can supply a **Hotfix** . [Contact Check Point Support](https://www.checkpoint.com/support-services/contact-support/) to get a Hotfix for this issue.  
A Support Engineer will make sure the Hotfix is compatible with your environment before providing the Hotfix.  
For faster resolution and verification, please collect [CPinfo files](http://supportcontent.checkpoint.com/solutions?id=sk92739) from the Security Management Server and Security Gateways involved in the case.

<br />

Code was improved. A Kernel parameter to control this behavior was added:  

* *adp_mc_rt_hold_queue_len*

To fix this issue follow this procedure:

1. Check for the current value of this parameter (Default value should be 4)

   **`ipsctl net:dev:adp:mcrt:hold_queue_len`**
2. Increase the value to '10' by editing $PPKDIR/conf/adpkern.conf:

   **`vi $PPKDIR/conf/adpkern.conf`**

   Add the line:

   **` adp_mc_rt_hold_queue_len=10`**
3. Reboot the Security Gateway.

   **Note:** This procedure needs to be implemented on all Cluster members.
4. Once the Gateway is rebooted, verify the changes by running the following command:

   **`ipsctl net:dev:adp:mcrt:hold_queue_len`**
5. Reproduce the issue with the same traffic that related to the drops and check if the issue is resolved.

6. In case the issue still persists, try to increase the Kernel parameter to its maximum size, which is '20'.

   In case the issue still persisting after changing to '20', [Contact Check Point Support.](https://www.checkpoint.com/support-services/contact-support/)

---

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