> Source: [sk111839](https://support.checkpoint.com/results/sk/sk111839)

# sk111839 - VPN Central Gateway drops SIP RTP traffic between the SIP Call Manager and the phone behind VPN Satellite Gateway, where the SIP call was initiated

| Property | Value |
|----------|-------|
| Solution ID | sk111839 |
| Date Created | 2016-06-06 |
| Last Modified | 2022-01-26 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R81.10 (EOS), R81 (EOS) |

## Symptoms

- * During SIP conference calls in a VPN Star community, some parties are unable to speak or be heard.

* VoIP traffic / call is functional in one direction only.

* Kernel debug on VPN Central Gateway ('`fw ctl debug -m fw + drop`' and '`fw ctl debug -m VPN + packet`') shows that it drops the SIP RTP traffic between the SIP Call Manager and the VPN Satellite Gateway where the SIP call was initiated:

  ```
  
  ;fw_log_drop: Packet proto=17 ... dropped by chain_ipsec_methods_ok Reason: vpn_decrypt_methods_ok failed;
  ... ...
  ;chain_ipsec_methods_ok: No decryption message;
  ... ...
  ;fw_log_drop: Packet proto=17 ... dropped by chain_ipsec_methods_ok Reason:  No decryption message;
  ... ...
  ```

  Another possible drop reason for the returned VoIP packets:

  ```
  
  ;fw_log_drop_ex: Packet proto=17 ... dropped by vpn_decrypt_verify Reason: CONN_ENC_NO_ENTRY[_SR] with packet reversed to the original direction of the connection;
  ```

## Solution

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