---
name: "four2six"
section: "8"
platform: "linux"
package: "thc-ipv6"
version: "3.8-4"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/four2six"
---

# four2six(8)

## NAME

**four2six**

## SYNOPSIS

four2six \[-FHD\] \[-m srcmac\] \[-s src6\] \[-p srcport\] interface ipv6-to-ipv4-gateway ipv4-src ipv4-dst \[port\]

## OPTIONS

```
  -F         insert atomic fragment header (can be set multiple times)
  -H         insert and empty hop-by-hop header
  -D         insert a large destination header that fragments the packet
  -p srcport  set a specific UDP source port or Ping ID
  -s src6    set a specific IPv6 source address
  -m srcmac  set a specific MAC source address
Send an IPv4 packet to an IPv6 4to6 gateway. If a port is specified, a UDP packet is sent, otherwise an ICMPv4 ping.
```

## AUTHOR

thc-ipv6 was written by van Hauser \<vh@thc.org\> / THC

The homepage for this toolkit is: https://github.com/vanhauser-thc/thc-ipv6

## COPYRIGHT

four2six 3.8 (c) 2020 by van Hauser / THC \<vh@thc.org\> www.github.com/vanhauser-thc/thc-ipv6