
EC2 Application Load Balancer supports storing HTTP access logs in S3. (These logs can be further analyzed in [[aws-bi-for-s3|Athena and QuickSight]]). It turns out the access logs capture [the user-agent](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent) request header. So if you want to know which service is behind the HTTP request, adjust the `user-agent` header in the service.

Here's an example from an AWS Lambda written in Typescript.

```typescript
import got from "got" // https://github.com/sindresorhus/got
got("https://example.com", {
  headers: {
    "user-agent": `Service: foo`,
  },
})
```


Marcel's notes

EC2 Application Load Balancer: Identifying clients by user-agents