---
name: "probe::netfilter.ip.post_routing"
section: "3stap"
platform: "linux"
package: "systemtap-doc"
version: "5.1-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/probe::netfilter.ip.post_routing"
---

# probe::netfilter.ip.post\_routing(3stap)

Called immediately before an outgoing IP packet leaves the computer

## NAME

probe::netfilter.ip.post\_routing - Called immediately before an outgoing IP packet leaves the computer

## SYNOPSIS

```
netfilter.ip.post_routing
```

## VALUES

*ipproto\_udp*

Constant used to signify that the packet protocol is UDP

*fin*

TCP FIN flag (if protocol is TCP; ipv4 only)

*data\_str*

A string representing the packet buffer contents

*iphdr*

Address of IP header

*psh*

TCP PSH flag (if protocol is TCP; ipv4 only)

*daddr*

A string representing the destination IP address

*nf\_stop*

Constant used to signify a 'stop' verdict

*nf\_queue*

Constant used to signify a 'queue' verdict

*protocol*

Packet protocol from driver (ipv4 only)

*ack*

TCP ACK flag (if protocol is TCP; ipv4 only)

*saddr*

A string representing the source IP address

*outdev\_name*

Name of network device packet will be routed to (if known)

*outdev*

Address of net\_device representing output device, 0 if unknown

*pf*

Protocol family -- either “ipv4” or “ipv6”

*sport*

TCP or UDP source port (ipv4 only)

*indev*

Address of net\_device representing input device, 0 if unknown

*nf\_stolen*

Constant used to signify a 'stolen' verdict

*syn*

TCP SYN flag (if protocol is TCP; ipv4 only)

*dport*

TCP or UDP destination port (ipv4 only)

*family*

IP address family

*ipproto\_tcp*

Constant used to signify that the packet protocol is TCP

*nf\_accept*

Constant used to signify an 'accept' verdict

*data\_hex*

A hexadecimal string representing the packet buffer contents

*nf\_repeat*

Constant used to signify a 'repeat' verdict

*length*

The length of the packet buffer contents, in bytes

*nf\_drop*

Constant used to signify a 'drop' verdict

*rst*

TCP RST flag (if protocol is TCP; ipv4 only)

*urg*

TCP URG flag (if protocol is TCP; ipv4 only)

*indev\_name*

Name of network device packet was received on (if known)

## SEE ALSO0

[*tapset::netfilter*(3stap)](/tapset::netfilter/3stap.md)