> Source: [sk181874](https://support.checkpoint.com/results/sk/sk181874)

# sk181874 - Dynamic Routing Manager failback causes "TCP out of state: First packet isn't SYN" drops

| Property | Value |
|----------|-------|
| Solution ID | sk181874 |
| Date Created | 2024-01-09 |
| Last Modified | 2024-07-01 |
| Technical Level | General |
| Products | Scalable Platforms |
| Versions | R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * After dynamic routing manager failure and recovery, connections are dropped with a log message "TCP out of state: First packet isn't SYN"
* Firewall kernel debug shows these connections were declared as zombie connections:  
  # fw ctl zdebug -m cluster + unisync  
  `
  fwha_iter_should_handle_conn: ERROR: no member will do iterator for this conn (zombie?).;`  
  `
  conn_entry_iterator_cb: Deleting zombie connection;`  
  `
  `

## Cause

This scenario is unique when two Security Gateway Modules (SGMs) are configured in the security group along with dynamic routing protocol and there are symmetric connections on the non-SMO Security Gateway Module.

In such scenario, a connection can be considered as a zombie connection and not synchronized on SGM-1 recovery phase.   
When SGM-1 is ready to be active again, the 'ROUTED' pnote is set on the SGM-2 to force its state to "Down" and moves the dynamic routing manager (DR manager) task back to SGM-1.

As the connection was not synchronized, it results in the connection drop  
`dropped by fw_first_packet_state_checks Reason: First packet isn't SYN;`

## Solution

This problem was fixed. The fix is included in:

* [Jumbo Hotfix Accumulator for R81.20](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.20/Default.htm) starting from Take 70
* [Jumbo Hotfix Accumulator for R81.10](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/Default.htm) starting from Take 141
* [Jumbo Hotfix Accumulator for R81](https://sc1.checkpoint.com/documents/Jumbo_HFA/R81/Default.htm) starting from Take 99

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.

**Hotfix installation instructions:**   
Refer to [sk168597 - How to install a Hotfix](https://support.checkpoint.com/results/sk/sk168597).

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