Documentation
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Overview ¶
Package dns implements a minimal UDP DNS server that answers A queries for <port>-<id>.<domain> hostnames with a configured IPv4 address. It exists so E2B SDK apps running in sibling Docker containers can resolve sandbox preview URLs to edvabe itself without relying on host-side wildcard DNS (lvh.me, nip.io) that only works from the host.
The server is intentionally single-purpose: it only answers A queries that match the configured base domain. Anything else gets REFUSED so misconfigured clients fail loud rather than silently black-holing unrelated lookups.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Server ¶
type Server struct {
Addr string // UDP listen address, e.g. ":53"
Domain string // base domain, e.g. "sbx.edvabe" — queried names must end with this
Answer net.IP // IPv4 to return in A records
Upstream string // host:port to forward non-matching queries to (e.g. "127.0.0.11:53"); empty disables forwarding
Logger *slog.Logger
}
Server answers A queries for *.Domain with Answer. Queries for names outside Domain are forwarded to Upstream if set; otherwise REFUSED.
Source Files