Using curl with ssh tunnels and a socks proxy - Thu, Mar 17, 2022

Using curl with ssh tunnels and a socks proxy

Where I work i often have to use several jump hosts to get to the machines in different environments (dev, ref, etc.). In order access http-based services that only run on those machines socks proxies are very useful.
Using a ssh config with DynamicForwards lets me connect directly to machines, multiple jumps away.
The following example shows the ssh config for one of those tunnels and the curl to access a loki instance on that machine:

Host loki-host
  HostName 172.16.0.2
  IdentityFile ~/.ssh/id_rsa
  User tom
  ForwardAgent yes
  ProxyJump jumphost
  Compression yes
  LogLevel QUIET
  DynamicForward 1337

Host jumphost
  HostName 192.168.10.1
  IdentityFile ~/.ssh/id_rsa
  User tom
  ForwardAgent yes
  Compression yes
  LogLevel QUIET
  DynamicForward 1337

$ curl --socks5-hostname localhost:1337 -G -s "http://localhost:3100/loki/api/v1/labels" | jq
{
  "status": "success",
  "data": [
    "__name__",
    "agent",
    "cluster",
    "filename",
    "job"
  ]
}

The ssh config lets me connect to loki-host without having to supply passwords. The command ssh loki-host will bring up the socks proxy on port 1337 which is then used by the curl. Please note that you should alter the NO_PROXY environment variable not to include localhost for this example (If you use one). Otherwise curl will try to use the proxy instead of the socks proxy.

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