> Source: [sk113503](https://support.checkpoint.com/results/sk/sk113503)

# sk113503 - SIP calls can not be established after installing Check Point Security Gateway between SIP phones and SIP server

| Property | Value |
|----------|-------|
| Solution ID | sk113503 |
| Date Created | 2016-09-22 |
| Last Modified | 2020-02-03 |
| Technical Level | Advanced |

## Symptoms

- * SIP calls can not be established after installing Check Point Security Gateway between SIP phones and SIP server when using a pre-defined UDP service "`sip_any`" in the Network Security policy.

* Neither SmartView Tracker / SmartLog, nor output of kernel debug '`fw ctl debug -m fw + drop`' on Check Point Security Gateway show any relevant drops of SIP traffic.

* Deleting the pre-defined UDP service "`sip_any`" from the relevant Network Security policy rule (i.e., using service "`Any`") and installing the policy resolves the issue.

## Cause

The SIP traffic does not comply with standards supported by Check Point Security Gateway (refer to [sk95369 - ATRG: VoIP](https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk95369)).

## Solution

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