> Source: [sk63688](https://support.checkpoint.com/results/sk/sk63688)

# sk63688 - BGP MD5 authentication problem after policy install

| Property | Value |
|----------|-------|
| Solution ID | sk63688 |
| Date Created | 2011-06-19 |
| Last Modified | 2012-05-13 |
| Technical Level | General |
| Products | Other |
| Versions | Not Version-Specific |

## Symptoms

- "TCP-6-BADAUTH: Invalid MD5 digest from \[Source IP\]:\[Source Port\] to \[Dest IP\]:179" error messages on Cisco routers when installing the policy, where a BGP session protected by md5 authentication is running.

## Cause

Connection Persistence is set to rematch connections. After the rematch, the sequence number is shifted in the TCP header. This leads to an invalid md5 calculation.

## Solution

Select "Keep connections open after Policy has been installed" checkbox on the BGP service.

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