TCP connection closes shortly after successful connect

[mortada-jafar]

I’m running slipstream-client and it accepts incoming TCP streams, but the connection gets closed soon after the connection is established. I’m trying to keep the TCP connection alive (or understand why it’s closing) and avoid the disconnect.

Command

slipstream-client-org \
  --domain=example.com \
  --resolver=1.1.1.1 \
  --tcp-listen-port=1000

Output / Logs

INFO Listening on TCP port 1000
INFO Accepted TCP stream 0
INFO Accepted TCP stream 4
INFO Accepted TCP stream 8
INFO Connection closed

[Mygod]

Likely the QUIC session never becomes ready, so the client accepts local TCP connections but then closes once picoquic gives up. The Connection closed line is emitted on the QUIC close/app-close/stateless-reset callback, not on TCP (crates/slipstream-client/src/streams.rs). If the user never sees Connection ready, the handshake didn’t complete, which usually means the DNS path isn’t delivering valid slipstream TXT responses.

Possible causes:

• Resolver path is blocked/poisoned (1.1.1.1 is often filtered), so DNS replies are missing or rewritten → no QUIC progress.
• Domain isn’t delegated to a slipstream-server. example.com is a placeholder; without an authoritative server you control, the resolver will return NXDOMAIN and the client ignores it (docs/protocol.md).
• Requests/responses are being dropped or truncated.

Quick checks to confirm:

• Look for Connection ready in logs; if absent, it’s a DNS/handshake failure.
• Ensure the domain actually points to your slipstream-server authoritative DNS.
• Run with RUST_LOG=debug plus --debug-poll/--debug-streams to see if any valid responses are arriving (crates/slipstream-client/src/runtime.rs).

If you can share whether Connection ready appears or what the debug poll logs show, I can narrow it down further.

Token usage: total=38,563 input=30,513 (+ 180,352 cached) output=8,050 (reasoning 6,976)
To continue this session, run codex resume 019bcfd1-a52e-7f50-8523-a842729fcf56

[mortada-jafar]

Server Command:

/root/slipstream-rust/target/release/slipstream-server \ --dns-listen-port 53 \ --target-address 127.0.0.1:1080 \ --domain example.com \ --cert /etc/slipstream/cert.pem \ --key /etc/slipstream/key.pem \ --debug-commands \ --debug-streams

Server Log:

Jan 18 10:30:35 quic slipstream-server[38768]: DEBUG debug: commands total=105 connected=6 connect_err=0 closed=2 readable=11 read_err=0 write_err=0 write_drained=86
Jan 18 10:30:35 quic slipstream-server[38768]: DEBUG stream 436: target eof read_bytes=12
Jan 18 10:30:35 quic slipstream-server[38768]: DEBUG stream 436: closed by target tx_bytes=12
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG debug: commands total=1136 connected=0 connect_err=0 closed=1 readable=5 read_err=0 write_err=0 write_drained=1130
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 440: connecting
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 440: target connected
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 416: target eof read_bytes=12
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 416: closed by target tx_bytes=2
Jan 18 10:30:36 quic slipstream-server[38768]:  WARN stream 416: reset event=stream_reset (unknown stream)
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 444: connecting
Jan 18 10:30:36 quic slipstream-server[38768]: DEBUG stream 444: target connected
Jan 18 10:30:37 quic slipstream-server[38768]: DEBUG debug: commands total=1571 connected=2 connect_err=0 closed=1 readable=4 read_err=0 write_err=0 write_drained=1564
Jan 18 10:30:38 quic slipstream-server[38768]: DEBUG stream 448: connecting
Jan 18 10:30:38 quic slipstream-server[38768]: DEBUG stream 448: target connected
Jan 18 10:30:38 quic slipstream-server[38768]: DEBUG debug: commands total=1152 connected=1 connect_err=0 closed=0 readable=2 read_err=0 write_err=0 write_drained=1149
Jan 18 10:30:38 quic slipstream-server[38768]: DEBUG stream 452: connecting
Jan 18 10:30:38 quic slipstream-server[38768]: DEBUG stream 452: target connected
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 452: target eof read_bytes=12
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 452: closed by target tx_bytes=12
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG debug: commands total=1391 connected=1 connect_err=0 closed=1 readable=6 read_err=0 write_err=0 write_drained=1383
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 456: connecting
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 460: connecting
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 464: connecting
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 456: target connected
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 460: target connected
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 464: target connected
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 468: connecting
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 468: target connected
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 444: target eof read_bytes=12
Jan 18 10:30:39 quic slipstream-server[38768]: DEBUG stream 444: closed by target tx_bytes=2
Jan 18 10:30:40 quic slipstream-server[38768]:  WARN stream 444: reset event=stream_reset (unknown stream)
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 472: connecting
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 476: connecting
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 480: connecting
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 472: target connected
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 476: target connected
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 480: target connected
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 428: target eof read_bytes=12
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 432: target eof read_bytes=12
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 428: closed by target tx_bytes=2
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG stream 432: closed by target tx_bytes=2
Jan 18 10:30:40 quic slipstream-server[38768]: DEBUG debug: commands total=1258 connected=7 connect_err=0 closed=3 readable=14 read_err=0 write_err=0 write_drained=1234
Jan 18 10:30:40 quic slipstream-server[38768]:  WARN stream 428: reset event=stream_reset (unknown stream)
Jan 18 10:30:40 quic slipstream-server[38768]:  WARN stream 432: reset event=stream_reset (unknown stream)
Jan 18 10:30:41 quic slipstream-server[38768]: DEBUG debug: commands total=1441 connected=0 connect_err=0 closed=0 readable=0 read_err=0 write_err=0 write_drained=1441
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 484: connecting
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 484: target connected
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG debug: commands total=1369 connected=1 connect_err=0 closed=0 readable=5 read_err=0 write_err=0 write_drained=1363
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 488: connecting
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 488: target connected
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 484: target eof read_bytes=12
Jan 18 10:30:42 quic slipstream-server[38768]: DEBUG stream 484: closed by target tx_bytes=12
Jan 18 10:30:43 quic slipstream-server[38768]: DEBUG debug: commands total=1511 connected=1 connect_err=0 closed=1 readable=3 read_err=0 write_err=0 write_drained=1506
Jan 18 10:30:43 quic slipstream-server[38768]: DEBUG stream 476: target eof read_bytes=12
Jan 18 10:30:43 quic slipstream-server[38768]: DEBUG stream 476: closed by target tx_bytes=2
Jan 18 10:30:43 quic slipstream-server[38768]:  WARN stream 476: reset event=stream_reset (unknown stream)
Jan 18 10:30:43 quic slipstream-server[38768]: DEBUG stream 492: connecting
Jan 18 10:30:43 quic slipstream-server[38768]: DEBUG stream 492: target connected
Jan 18 10:30:44 quic slipstream-server[38768]: DEBUG debug: commands total=1383 connected=1 connect_err=0 closed=1 readable=2 read_err=0 write_err=0 write_drained=1379
Jan 18 10:30:45 quic slipstream-server[38768]: DEBUG stream 472: target eof read_bytes=12
Jan 18 10:30:45 quic slipstream-server[38768]: DEBUG stream 472: closed by target tx_bytes=2
Jan 18 10:30:45 quic slipstream-server[38768]: DEBUG stream 480: target eof read_bytes=12
Jan 18 10:30:45 quic slipstream-server[38768]: DEBUG stream 480: closed by target tx_bytes=2
Jan 18 10:30:45 quic slipstream-server[38768]: DEBUG debug: commands total=4 connected=0 connect_err=0 closed=2 readable=2 read_err=0 write_err=0 write_drained=0
Jan 18 10:30:46 quic slipstream-server[38768]: DEBUG stream 492: target eof read_bytes=12
Jan 18 10:30:46 quic slipstream-server[38768]: DEBUG stream 492: closed by target tx_bytes=2
Jan 18 10:30:47 quic slipstream-server[38768]: DEBUG debug: commands total=2 connected=0 connect_err=0 closed=1 readable=1 read_err=0 write_err=0 write_drained=0

Client Command:

RUST_LOG=info ./slipstream-client--tcp-listen-port=8090 --resolver=1.1.1.1 --domain example.com --debug-poll --debug-streams

Client Log:

DEBUG stream 328: accepted
DEBUG stream 332: accepted
DEBUG stream 336: accepted
DEBUG stream 340: accepted
DEBUG stream 344: accepted
DEBUG stream 344: finished
DEBUG stream 348: accepted
 WARN stream 320: tcp read error (unknown stream)
DEBUG stream 352: accepted
DEBUG debug: dns+=1084 send_pkts+=1104 send_bytes+=157351 polls+=5 zero_send+=778 zero_send_streams+=778 streams=50 enqueued+=136619 last_enqueue_ms=53 pending_polls=10 inflight_polls=0
DEBUG debug: dns+=1114 send_pkts+=1174 send_bytes+=167607 polls+=4 zero_send+=696 zero_send_streams+=696 streams=50 enqueued+=249 last_enqueue_ms=128 pending_polls=10 inflight_polls=0
DEBUG stream 356: accepted
DEBUG debug: dns+=1292 send_pkts+=1282 send_bytes+=182724 polls+=14 zero_send+=772 zero_send_streams+=772 streams=51 enqueued+=134270 last_enqueue_ms=14 pending_polls=10 inflight_polls=0
DEBUG stream 360: accepted
DEBUG stream 364: accepted
DEBUG stream 368: accepted
DEBUG debug: dns+=1441 send_pkts+=1592 send_bytes+=227629 polls+=9 zero_send+=829 zero_send_streams+=829 streams=54 enqueued+=3160 last_enqueue_ms=15 pending_polls=10 inflight_polls=0
DEBUG stream 372: accepted
DEBUG stream 376: accepted
DEBUG debug: dns+=1869 send_pkts+=2035 send_bytes+=290922 polls+=31 zero_send+=822 zero_send_streams+=822 streams=54 enqueued+=1001 last_enqueue_ms=82 pending_polls=10 inflight_polls=0
DEBUG stream 376: finished
DEBUG stream 380: accepted
 WARN stream 340: tcp read error (unknown stream)
 WARN stream 336: tcp read error (unknown stream)
DEBUG stream 384: accepted
DEBUG stream 388: accepted
DEBUG stream 380: finished
DEBUG stream 392: accepted
DEBUG stream 396: accepted
DEBUG debug: dns+=2192 send_pkts+=2555 send_bytes+=365279 polls+=40 zero_send+=1002 zero_send_streams+=1002 streams=55 enqueued+=266117 last_enqueue_ms=69 pending_polls=10 inflight_polls=0
DEBUG stream 400: accepted
 WARN stream 352: tcp read error (unknown stream)
DEBUG stream 404: accepted
DEBUG stream 408: accepted
DEBUG stream 412: accepted
DEBUG debug: dns+=2489 send_pkts+=3276 send_bytes+=468377 polls+=78 zero_send+=1019 zero_send_streams+=1019 streams=58 enqueued+=307765 last_enqueue_ms=12 pending_polls=10 inflight_polls=0
 WARN stream 400: tcp read error (unknown stream)
DEBUG debug: dns+=3193 send_pkts+=3769 send_bytes+=538831 polls+=121 zero_send+=919 zero_send_streams+=919 streams=57 enqueued+=123317 last_enqueue_ms=397 pending_polls=10 inflight_polls=0
DEBUG stream 416: accepted
DEBUG stream 420: accepted
DEBUG stream 424: accepted
DEBUG debug: dns+=2236 send_pkts+=2234 send_bytes+=318522 polls+=117 zero_send+=938 zero_send_streams+=938 streams=60 enqueued+=394540 last_enqueue_ms=253 pending_polls=10 inflight_polls=0
 WARN stream 364: tcp read error (unknown stream)
 WARN stream 368: tcp read error (unknown stream)
DEBUG stream 428: accepted
DEBUG stream 432: accepted
DEBUG stream 436: accepted
DEBUG stream 436: finished
DEBUG debug: dns+=1823 send_pkts+=1795 send_bytes+=255798 polls+=52 zero_send+=754 zero_send_streams+=754 streams=60 enqueued+=467 last_enqueue_ms=264 pending_polls=10 inflight_polls=0
DEBUG stream 440: accepted
 WARN stream 416: tcp read error (unknown stream)
DEBUG stream 444: accepted
DEBUG debug: dns+=2563 send_pkts+=1927 send_bytes+=275312 polls+=16 zero_send+=996 zero_send_streams+=996 streams=61 enqueued+=394891 last_enqueue_ms=108 pending_polls=10 inflight_polls=0
DEBUG debug: dns+=2156 send_pkts+=1687 send_bytes+=240953 polls+=6 zero_send+=785 zero_send_streams+=785 streams=61 enqueued+=0 last_enqueue_ms=1108 pending_polls=10 inflight_polls=0
DEBUG stream 448: accepted
DEBUG stream 452: accepted
DEBUG debug: dns+=1605 send_pkts+=1671 send_bytes+=238342 polls+=19 zero_send+=747 zero_send_streams+=747 streams=63 enqueued+=16 last_enqueue_ms=57 pending_polls=10 inflight_polls=0
DEBUG stream 452: finished
DEBUG debug: dns+=2038 send_pkts+=1640 send_bytes+=234409 polls+=25 zero_send+=894 zero_send_streams+=894 streams=62 enqueued+=526478 last_enqueue_ms=504 pending_polls=10 inflight_polls=0
DEBUG stream 456: accepted
DEBUG stream 460: accepted
DEBUG stream 464: accepted
DEBUG stream 468: accepted
 WARN stream 444: tcp read error (unknown stream)
DEBUG stream 472: accepted
DEBUG stream 476: accepted
DEBUG stream 480: accepted
 WARN stream 428: tcp read error (unknown stream)
 WARN stream 432: tcp read error (unknown stream)
DEBUG debug: dns+=1876 send_pkts+=1723 send_bytes+=246376 polls+=7 zero_send+=813 zero_send_streams+=813 streams=66 enqueued+=91 last_enqueue_ms=600 pending_polls=10 inflight_polls=0
DEBUG debug: dns+=1703 send_pkts+=1685 send_bytes+=240879 polls+=28 zero_send+=756 zero_send_streams+=756 streams=66 enqueued+=0 last_enqueue_ms=1600 pending_polls=10 inflight_polls=0
DEBUG stream 484: accepted
DEBUG stream 488: accepted
DEBUG stream 484: finished
DEBUG debug: dns+=1718 send_pkts+=1756 send_bytes+=251032 polls+=9 zero_send+=935 zero_send_streams+=935 streams=67 enqueued+=525950 last_enqueue_ms=17 pending_polls=10 inflight_polls=0
 WARN stream 476: tcp read error (unknown stream)
DEBUG stream 492: accepted
DEBUG debug: dns+=1845 send_pkts+=1873 send_bytes+=267732 polls+=18 zero_send+=789 zero_send_streams+=789 streams=67 enqueued+=13 last_enqueue_ms=44 pending_polls=10 inflight_polls=0
 INFO Connection closed
ERROR Client error: Network is unreachable (os error 101)

Note:
The tunnel disconnects after some time (it is not immediate).
It usually happens under real traffic/load — for example while uploading a file.

[Mygod]

The behavior matches a flaky recursive path rather than a local client bug. In recursive mode, the resolver still has to reach your authoritative slipstream server; if that leg is intermittently blocked or rate‑limited (common under firewall/anycast changes), the tunnel will sometimes work and then drop under load.

Separately, your server logs show the target at 127.0.0.1:1080 closing immediately (target eof read_bytes=12), which suggests a protocol mismatch (looks like a SOCKS reply). That will close individual streams even if the tunnel itself is healthy.

What you can do if recursive is mandatory:

• Use multiple --resolver entries from different providers/ASNs to avoid a single flaky path.

We’ve also updated the client/server to treat EHOSTUNREACH/ENETUNREACH as transient so they don’t exit on ICMP unreachable (f3fa1f8), but if DNS responses stop entirely the tunnel will still stall.