> Source: [sk113239](https://support.checkpoint.com/results/sk/sk113239)

# sk113239 - NAT is not performed on payload of SIP traffic 

| Property | Value |
|----------|-------|
| Solution ID | sk113239 |
| Date Created | 2016-09-06 |
| Last Modified | 2016-09-07 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- * NAT is not performed on payload of SIP traffic.
* Kernel debug ('`fw ctl debug -m fw + tcpstr`' and '`fw ctl debug -m WS + parser`') shows:

  `
  ;Date Time;[cpu_X];[fwY];...:{parser} ws_parser_check_fastpath: [WARNING]: ws_strict_parsing is set ...`  
  `
  ...`  
  `
  ;Date Time;[cpu_X];[fwY];...:{parser} ws_parse_request_line: [WARNING]: Unknown method found in request;`  
  `
  ...`  
  `
  ;Date Time;[cpu_X];[fwY];...:{parser} ws_parse_request_line: [WARNING]: method SIP/2.0 is unknown to parser;`  
  `
  ...`  
  `
  ;Date Time;[cpu_X];[fwY];...:{parser} ws_parse_request_line: [WARNING]: request parsing failed due to a malformed HTTP version;`  
  `
  ...`  
  `
  ;Date Time;[cpu_X];[fwY];sip_ws_parser: Parsing failed!;`  
  `
  ;Date Time;[cpu_X];[fwY];sip_run_parser: Generic parsing failed;
  `

## Cause

Strict parsing is currently enabled, and does not allow special characters in SIP payload.

## Solution

This solution requires authentication. Please log in to view the full solution.

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