Use a private subnet for the tutorial network - #12
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SUBNET was 182.18.1.0/24, which is public address space allocated to APNIC - not a private range. Every other NGSI-LD tutorial hardcodes 172.18.1.0/24 in docker-compose/common.yml; this is the only one that parameterises the subnet. The effect is that the stack appears to start correctly and is then unreachable from the host: docker publishes the port, the container reports healthy, and a request to localhost:1026 TIMES OUT rather than being refused, because the container's address (182.18.1.8) is a real internet host as far as the kernel's routing is concerned. It also occupies 256 public addresses on the machine running it. With 172.18.1.0/24 the tutorial runs.
jason-fox
approved these changes
Sep 21, 2026
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SUBNETin.envis182.18.1.0/24, which is public address space allocated to APNIC — not a private range. Every other NGSI-LD tutorial hardcodes172.18.1.0/24indocker-compose/common.yml; this is the only one that parameterises the subnet.Why it's hard to spot
The stack appears to start perfectly:
./services coraineexits 0docker psshows0.0.0.0:1026->1026/tcpand then nothing answers:
A bound port that accepts and never replies, because as far as the host's routing is concerned
182.18.1.8is a machine on the internet.It also occupies 256 public addresses on whatever machine runs the tutorial.
The change
One line:
SUBNET=172.18.1.0/24, matching every other tutorial. With it, the tutorial runs.Found while running all sixteen NGSI-LD tutorials against a different NGSI-LD broker; this was the only one that could not be started at all.