POSTROUTING
E886827
POSTROUTING is a Netfilter hook in the Linux kernel networking stack that processes packets just before they leave the system, typically used for tasks like network address translation (NAT).
All labels observed (1)
| Label | Occurrences |
|---|---|
| POSTROUTING canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T10826892 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: POSTROUTING Context triple: [netfilter, hasHook, POSTROUTING]
-
A.
NAT
NAT is the station code used to identify Nationaltheatret railway station in Oslo, Norway.
-
B.
Postfix
Postfix is a widely used open-source mail transfer agent (MTA) for Unix-like systems, designed as a secure, fast, and easy-to-administer alternative to Sendmail.
-
C.
NAT-T
NAT-T (NAT Traversal) is an IPsec extension that enables VPN traffic to pass through Network Address Translation devices by encapsulating IPsec packets in UDP.
-
D.
Pasca
Pasca is a town in Colombia’s Cundinamarca Department, known as the discovery site of the famous pre-Columbian Muisca golden raft artifact.
-
E.
Poston
Poston is a surname most notably associated with American actor and comedian Tom Poston.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: POSTROUTING Target entity description: POSTROUTING is a Netfilter hook in the Linux kernel networking stack that processes packets just before they leave the system, typically used for tasks like network address translation (NAT).
-
A.
NAT
NAT is the station code used to identify Nationaltheatret railway station in Oslo, Norway.
-
B.
Postfix
Postfix is a widely used open-source mail transfer agent (MTA) for Unix-like systems, designed as a secure, fast, and easy-to-administer alternative to Sendmail.
-
C.
NAT-T
NAT-T (NAT Traversal) is an IPsec extension that enables VPN traffic to pass through Network Address Translation devices by encapsulating IPsec packets in UDP.
-
D.
Pasca
Pasca is a town in Colombia’s Cundinamarca Department, known as the discovery site of the famous pre-Columbian Muisca golden raft artifact.
-
E.
Poston
Poston is a surname most notably associated with American actor and comedian Tom Poston.
- F. None of above. chosen
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
Linux kernel networking concept
ⓘ
Netfilter hook ⓘ |
| appliesTo |
forwarded packets
ⓘ
locally generated packets ⓘ outgoing packets ⓘ |
| belongsTo | kernel space networking ⓘ |
| canModify |
packet headers
ⓘ
source IP address ⓘ source port ⓘ |
| commonUse |
Masquerading
ⓘ
Network Address Translation ⓘ Packet mangling ⓘ Source NAT ⓘ |
| configuredVia |
iptables -t nat -A POSTROUTING
ⓘ
nftables postrouting chain ⓘ |
| direction | egress ⓘ |
| documentation | Linux kernel Netfilter documentation ⓘ |
| effectOnRouting |
applies after routing is completed
ⓘ
does not change routing decision ⓘ |
| ensures | packets are rewritten before transmission ⓘ |
| environment | kernel space ⓘ |
| executionOrder |
after FORWARD hook
ⓘ
after OUTPUT hook ⓘ |
| hasRole | packet processing hook ⓘ |
| hookNumber | NF_INET_POST_ROUTING ⓘ |
| implementationLanguage | C ⓘ |
| introducedFor | flexible packet filtering and NAT in Linux ⓘ |
| layer | IP layer ⓘ |
| partOf |
Linux kernel networking stack
ⓘ
linked to:
Linux kernel subsystems
Netfilter framework ⓘ
linked to:
netfilter
|
| positionInPipeline | just before packets leave the system ⓘ |
| primaryAdministratorUse | configuring NAT on routers and gateways ⓘ |
| relatedConcept |
FORWARD
ⓘ
INPUT ⓘ OUTPUT ⓘ PREROUTING ⓘ |
| scope |
IPv4
ⓘ
IPv6 ⓘ |
| tableUsedWith |
mangle table
ⓘ
nat table ⓘ |
| triggeredWhen | packet is about to be sent out an interface ⓘ |
| usedBy |
firewall administrators
ⓘ
network engineers ⓘ |
| usedIn |
Linux operating system
ⓘ
linked to:
Linux
iptables ⓘ nftables ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: POSTROUTING Description of subject: POSTROUTING is a Netfilter hook in the Linux kernel networking stack that processes packets just before they leave the system, typically used for tasks like network address translation (NAT).
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.