> Source: [sk180847](https://support.checkpoint.com/results/sk/sk180847)

# sk180847 - TX errors on a 6in4 "sit" interface

| Property | Value |
|----------|-------|
| Solution ID | sk180847 |
| Date Created | 2023-04-21 |
| Last Modified | 2023-05-11 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * Output of the "`ifconfig sit_6in4_<X>`" command shows a large number in the "TX" line in the "errors" counter.

* Output of the "`ethtool -S <Physical Interface>`" command does not show TX errors.

## Cause

General TX errors can appear on a 6-in-4 "sit" interface due to these factors:

* An ingress packet is not an IPv6 packet
* An ingress packet is an ISATAP packet (<https://datatracker.ietf.org/doc/html/rfc4214>)
* If the nexthop destination of the packet is "null", not reachable, and so on
* An ingress packet exceeds the interface's MTU
* Packet encapsulation failed

## Solution

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

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