> Source: [sk102835](https://support.checkpoint.com/results/sk/sk102835)

# sk102835 - VPN tunnel fails after an IPS update

| Property | Value |
|----------|-------|
| Solution ID | sk102835 |
| Date Created | 2014-10-07 |
| Last Modified | 2014-11-27 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20 |

## Symptoms

- * VPN tunnel fails after an IPS update.

* Kernel debug on problematic Security Gateway ('`fw ctl debug -m fw + drop`') shows that IKE traffic (UDP port 500) is dropped:  

  `fw_log_drop_ex: Packet proto=17 `*Source_IP* `:500 -> `*Dest_IP*`:500 dropped by fwpslglue_chain Reason: PSL Drop: ASPII_MT;`

## Cause

IKE Phase 1 Main Mode packet # 5 is dropped by IPS protection "`TCPDUMP ISAKMP Payload Handling DoS`" (CVE-2004-0183 , CPAI-2004-131).

## Solution

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