diff --git a/man/httrack.1 b/man/httrack.1
index 96c3f3a0..33f729b6 100644
--- a/man/httrack.1
+++ b/man/httrack.1
@@ -3,7 +3,7 @@
 .\"
 .\" This file is generated by man/makeman.sh; do not edit by hand.
 .\" SPDX-License-Identifier: GPL-3.0-or-later
-.TH httrack 1 "14 July 2026" "httrack website copier"
+.TH httrack 1 "16 July 2026" "httrack website copier"
 .SH NAME
 httrack \- offline browser : copy websites to a local directory
 .SH SYNOPSIS
@@ -165,7 +165,7 @@ pause transfer if N bytes reached, and wait until lock file is deleted (\-\-max\
 .IP \-cN
 number of multiple connections (*c8) (\-\-sockets[=N])
 .IP \-TN
-timeout, number of seconds after a non\-responding link is shutdown (\-\-timeout[=N])
+timeout, number of seconds after a non\-responding link is shutdown; also bounds host name resolution (\-\-timeout[=N])
 .IP \-RN
 number of retries, in case of timeout or non\-fatal errors (*R1) (\-\-retries[=N])
 .IP \-JN
diff --git a/src/htsdns_selftest.c b/src/htsdns_selftest.c
index 101eb2e9..3673fe4e 100644
--- a/src/htsdns_selftest.c
+++ b/src/htsdns_selftest.c
@@ -63,9 +63,14 @@ typedef struct mock_host {
   int gai_err; /* non-zero: getaddrinfo returns this */
   int naddr;
   mock_addr addr[6];
-  int calls; /* times the backend resolved this host */
+  int calls;   /* times the backend resolved this host */
+  int slow_ms; /* non-zero: block this long, as a black-hole resolver would */
 } mock_host;
 
+/* Long enough to outlast the 1s --timeout the bounded resolve is checked
+   against, short enough to keep the self-test quick. */
+#define MOCK_SLOW_MS 3000
+
 static mock_host mock_hosts[] = {
     {"v4only.test", 0, 1, {{AF_INET, {1, 2, 3, 4}}}, 0},
     {"v6only.test", 0, 1, {{AF_INET6, {0x20, 0x01, 0x0d, 0xb8, [15] = 1}}}, 0},
@@ -95,8 +100,15 @@ static mock_host mock_hosts[] = {
       {AF_INET, {10, 0, 0, 6}}},
      0},
     {"nodns.test", EAI_NONAME, 0, {{0}}, 0},
+    /* resolves, but only well after --timeout: the #606 wedge */
+    {"slow.test", 0, 1, {{AF_INET, {127, 0, 0, 9}}}, 0, MOCK_SLOW_MS},
 };
 
+/* Serializes mock_host bookkeeping: a timed-out resolve is abandoned, so its
+   worker is still inside the backend while the test reads the counters. */
+static htsmutex mock_lock = HTSMUTEX_INIT;
+static int mock_finished = 0; /* backend calls that have returned */
+
 static mock_host *mock_find(const char *name) {
   for (size_t i = 0; i < sizeof(mock_hosts) / sizeof(mock_hosts[0]); i++) {
     if (strcmp(mock_hosts[i].name, name) == 0)
@@ -106,8 +118,34 @@ static mock_host *mock_find(const char *name) {
 }
 
 static void mock_reset_calls(void) {
+  hts_mutexlock(&mock_lock);
   for (size_t i = 0; i < sizeof(mock_hosts) / sizeof(mock_hosts[0]); i++)
     mock_hosts[i].calls = 0;
+  mock_finished = 0;
+  hts_mutexrelease(&mock_lock);
+}
+
+static int mock_read_calls(const char *name) {
+  int calls;
+
+  hts_mutexlock(&mock_lock);
+  calls = mock_find(name)->calls;
+  hts_mutexrelease(&mock_lock);
+  return calls;
+}
+
+/* Wait for n backend calls to return, ordering their writes against ours. */
+static void mock_wait_finished(int n) {
+  for (;;) {
+    hts_boolean done;
+
+    hts_mutexlock(&mock_lock);
+    done = (mock_finished >= n) ? HTS_TRUE : HTS_FALSE;
+    hts_mutexrelease(&mock_lock);
+    if (done)
+      break;
+    Sleep(10);
+  }
 }
 
 /* Build one addrinfo node owning its sockaddr (freed by mock_freeaddrinfo). */
@@ -133,10 +171,10 @@ static struct addrinfo *mock_mkai(const mock_addr *a) {
   return ai;
 }
 
-static int HTS_RESOLVER_CALL mock_getaddrinfo(const char *node,
-                                              const char *service,
-                                              const struct addrinfo *hints,
-                                              struct addrinfo **res) {
+static int HTS_RESOLVER_CALL mock_getaddrinfo_(const char *node,
+                                               const char *service,
+                                               const struct addrinfo *hints,
+                                               struct addrinfo **res) {
   mock_host *const h = mock_find(node);
   const int want = (hints != NULL) ? hints->ai_family : PF_UNSPEC;
   struct addrinfo *head = NULL, *tail = NULL;
@@ -145,7 +183,11 @@ static int HTS_RESOLVER_CALL mock_getaddrinfo(const char *node,
   *res = NULL;
   if (h == NULL)
     return EAI_NONAME;
+  hts_mutexlock(&mock_lock);
   h->calls++; /* a real backend hit; a cached host skips this */
+  hts_mutexrelease(&mock_lock);
+  if (h->slow_ms != 0)
+    Sleep(h->slow_ms);
   if (h->gai_err != 0)
     return h->gai_err;
   for (int i = 0; i < h->naddr; i++) {
@@ -165,6 +207,18 @@ static int HTS_RESOLVER_CALL mock_getaddrinfo(const char *node,
   return 0;
 }
 
+static int HTS_RESOLVER_CALL mock_getaddrinfo(const char *node,
+                                              const char *service,
+                                              const struct addrinfo *hints,
+                                              struct addrinfo **res) {
+  const int ret = mock_getaddrinfo_(node, service, hints, res);
+
+  hts_mutexlock(&mock_lock);
+  mock_finished++;
+  hts_mutexrelease(&mock_lock);
+  return ret;
+}
+
 static void HTS_RESOLVER_CALL mock_freeaddrinfo(struct addrinfo *res) {
   while (res != NULL) {
     struct addrinfo *const next = res->ai_next;
@@ -370,6 +424,91 @@ int dns_selftests(httrackp *opt) {
   return failures;
 }
 
+/* Probes how long acquiring opt->state.lock takes while a resolve is in
+   flight. hts_has_stopped() takes that same lock and mutates nothing, and the
+   API promises it stays callable from another thread during a mirror. */
+typedef struct lock_probe {
+  httrackp *opt;
+  htsmutex lock;
+  hts_boolean done;
+  TStamp blocked_ms;
+} lock_probe;
+
+static void lock_probe_thread(void *arg) {
+  lock_probe *const p = (lock_probe *) arg;
+  TStamp start;
+
+  Sleep(MOCK_SLOW_MS / 10); /* let the resolve get under way first */
+  start = mtime_local();
+  (void) hts_has_stopped(p->opt);
+  hts_mutexlock(&p->lock);
+  p->blocked_ms = mtime_local() - start;
+  p->done = HTS_TRUE;
+  hts_mutexrelease(&p->lock);
+}
+
+int dns_timeout_selftests(httrackp *opt) {
+  SOCaddr addrs[HTS_MAXADDRNUM];
+  const char *err = NULL;
+  lock_probe probe;
+  TStamp start, elapsed;
+  int count;
+
+  failures = 0;
+  hts_dns_set_resolver_backend(&mock_backend);
+  IPV6_resolver = 0;
+  mock_reset_calls();
+  opt->timeout = 1; /* the bound under test */
+
+  memset(&probe, 0, sizeof(probe));
+  probe.opt = opt;
+  probe.lock = HTSMUTEX_INIT;
+  hts_mutexinit(&probe.lock);
+  CHECK(hts_newthread(lock_probe_thread, &probe) == 0);
+
+  start = mtime_local();
+  count = hts_dns_resolve_all(opt, "slow.test", addrs, HTS_MAXADDRNUM, &err);
+  elapsed = mtime_local() - start;
+
+  /* the resolve returns on opt->timeout, not when the resolver deigns to
+     answer: this is what lets --max-time and --timeout fire (#606). The bound
+     is derived from opt->timeout, never from the mock's sleep, or a resolve
+     that ignored opt->timeout would still pass under the mock. */
+  CHECK(elapsed < (TStamp) opt->timeout * 1000 + 500);
+  CHECK(count == 0); /* a timeout is reported as "does not resolve" */
+
+  /* state.lock is not held across the resolve; a concurrent stop query, which
+     the mirror API promises stays live, is not blocked behind it */
+  for (;;) {
+    hts_boolean done;
+    TStamp blocked;
+
+    hts_mutexlock(&probe.lock);
+    done = probe.done;
+    blocked = probe.blocked_ms;
+    hts_mutexrelease(&probe.lock);
+    if (done) {
+      CHECK(blocked < 500);
+      break;
+    }
+    Sleep(20);
+  }
+  hts_mutexfree(&probe.lock);
+
+  /* a timeout is not an answer, so it must not be negative-cached: the host is
+     resolved again rather than written off for the rest of the crawl */
+  CHECK(mock_read_calls("slow.test") == 1);
+  count = hts_dns_resolve_all(opt, "slow.test", addrs, HTS_MAXADDRNUM, &err);
+  CHECK(count == 0);
+  CHECK(mock_read_calls("slow.test") == 2); /* re-resolved, not cached */
+
+  /* Both resolves were abandoned mid-backend; wait for their workers to leave
+     it before returning. The backend stays installed: an abandoned worker
+     still reads it (to free its addrinfo) after the last call returns. */
+  mock_wait_finished(2);
+  return failures;
+}
+
 #else
 
 int dns_selftests(httrackp *opt) {
diff --git a/src/htsdns_selftest.h b/src/htsdns_selftest.h
index 72b34d8c..74a6062b 100644
--- a/src/htsdns_selftest.h
+++ b/src/htsdns_selftest.h
@@ -46,6 +46,12 @@ typedef struct httrackp httrackp;
    Returns the number of failed checks (0 == success). */
 int dns_selftests(httrackp *opt);
 
+/* Drive a deliberately slow (mock) resolver, asserting that a resolve is
+   bounded by opt->timeout, does not hold opt->state.lock while it runs, and
+   does not cache a timeout as an answer (#606). Takes a few seconds.
+   Returns the number of failed checks (0 == success). */
+int dns_timeout_selftests(httrackp *opt);
+
 #endif
 
 #endif
diff --git a/src/htshelp.c b/src/htshelp.c
index 9d3db084..e48921ee 100644
--- a/src/htshelp.c
+++ b/src/htshelp.c
@@ -496,8 +496,8 @@ void help(const char *app, int more) {
   infomsg("");
   infomsg("Flow control:");
   infomsg("  cN number of multiple connections (*c8)");
-  infomsg
-    ("  TN timeout, number of seconds after a non-responding link is shutdown");
+  infomsg("  TN timeout, number of seconds after a non-responding link is"
+          " shutdown; also bounds host name resolution");
   infomsg
     ("  RN number of retries, in case of timeout or non-fatal errors (*R1)");
   infomsg
diff --git a/src/htslib.c b/src/htslib.c
index 55899b26..8687152a 100644
--- a/src/htslib.c
+++ b/src/htslib.c
@@ -5084,50 +5084,164 @@ HTSEXT_API int check_hostname_dns(const char *const hostname) {
   return hts_dns_resolve_nocache(hostname, &buffer) != NULL;
 }
 
-// Needs locking
-// Internal DNS cache. Fill out[0..count-1] with up to max addresses for _iadr,
-// resolving (and caching the full list) on a miss. Returns the count.
-static int hts_dns_resolve_list_(httrackp *opt, const char *_iadr,
-                                 SOCaddr *const out, const int max,
-                                 const char **error) {
-  char BIGSTK iadr[HTS_URLMAXSIZE * 2];
-  coucal cache = hts_cache(opt); // le cache dns
+/* A resolve in flight. Refcounted: a timed-out resolve is abandoned, not
+   cancelled, so the last of caller/worker to leave frees the job. */
+typedef struct dns_resolve_job {
+  htsmutex lock;
+  int refcount;
+  hts_boolean done;
+  char *hostname;
+  SOCaddr addr[HTS_MAXADDRNUM];
   int count;
+  const char *error;
+} dns_resolve_job;
+
+/* Copy the first min(count, max) addresses of src into dest. */
+static void dns_copy_addrs(SOCaddr *dest, SOCaddr *src, int count, int max) {
+  int i;
+
+  for (i = 0; i < count && i < max; i++)
+    SOCaddr_copy_SOCaddr(dest[i], src[i]);
+}
+
+static void dns_job_release(dns_resolve_job *job) {
+  hts_boolean last;
+
+  hts_mutexlock(&job->lock);
+  last = (--job->refcount == 0) ? HTS_TRUE : HTS_FALSE;
+  hts_mutexrelease(&job->lock);
+  if (last) {
+    hts_mutexfree(&job->lock);
+    freet(job->hostname);
+    freet(job);
+  }
+}
+
+/* Outlives a timed-out resolve, so it writes only the job: never opt (freed
+   before the thread wait at exit) nor the DNS cache. */
+static void dns_resolve_thread(void *arg) {
+  dns_resolve_job *const job = (dns_resolve_job *) arg;
+  SOCaddr resolved[HTS_MAXADDRNUM];
+  const char *error = NULL;
+  const int count = hts_dns_resolve_nocache_list(job->hostname, resolved,
+                                                 HTS_MAXADDRNUM, &error);
+
+  hts_mutexlock(&job->lock);
+  dns_copy_addrs(job->addr, resolved, count, HTS_MAXADDRNUM);
+  job->count = count;
+  job->error = error;
+  job->done = HTS_TRUE; /* published last: gates the caller's read of addr[] */
+  hts_mutexrelease(&job->lock);
+  dns_job_release(job);
+}
+
+/* Resolve hostname on a worker thread, giving up after timeout seconds.
+   Returns the address count, or -1 on timeout -- distinct from 0 ("does not
+   resolve"), which is a real answer and gets negative-cached. */
+static int hts_dns_resolve_nocache_list_bounded(const char *hostname,
+                                                SOCaddr *const out,
+                                                const int max,
+                                                const int timeout,
+                                                const char **error) {
+  dns_resolve_job *job;
+  TStamp deadline;
+  int count = -1;
+  int poll_ms = 1;
+
+  if (timeout <= 0) /* no bound asked for (--timeout 0) */
+    return hts_dns_resolve_nocache_list(hostname, out, max, error);
+
+  job = calloct(1, sizeof(*job));
+  assertf(job != NULL);
+  hts_mutexinit(&job->lock);
+  job->hostname = strdupt(hostname);
+  job->refcount = 2; /* this caller + the worker */
+  if (hts_newthread(dns_resolve_thread, job) != 0) {
+    job->refcount = 1; /* no worker: fall back to resolving inline */
+    dns_job_release(job);
+    return hts_dns_resolve_nocache_list(hostname, out, max, error);
+  }
+
+  deadline = mtime_local() + (TStamp) timeout * 1000;
+  for (;;) {
+    hts_boolean done;
+
+    hts_mutexlock(&job->lock);
+    done = job->done;
+    if (done) {
+      count = job->count;
+      dns_copy_addrs(out, job->addr, count, max);
+      if (error != NULL)
+        *error = job->error;
+    }
+    hts_mutexrelease(&job->lock);
+    if (done || mtime_local() >= deadline)
+      break;
+    Sleep(poll_ms);
+    if (poll_ms < 50) /* short first polls keep a fast resolve fast */
+      poll_ms *= 2;
+  }
+  dns_job_release(job);
+  return count;
+}
+
+int hts_dns_resolve_all(httrackp *opt, const char *iadr, SOCaddr *out, int max,
+                        const char **error) {
+  char BIGSTK host[HTS_URLMAXSIZE * 2];
+  SOCaddr resolved[HTS_MAXADDRNUM];
+  coucal cache;
+  int count, i;
 
   assertf(opt != NULL);
-  assertf(_iadr != NULL);
   assertf(out != NULL);
+  if (!strnotempty(iadr) || max <= 0) {
+    return 0;
+  }
 
-  strcpybuff(iadr, jump_identification_const(_iadr));
-  // couper éventuel :
+  /* cache key and resolver input: identification and any ":port" stripped */
+  strcpybuff(host, jump_identification_const(iadr));
   {
     char *a;
 
-    if ((a = jump_toport(iadr)))
+    if ((a = jump_toport(host)))
       *a = '\0';
   }
 
-  /* get IP from the dns cache */
-  count = hts_ghbn_all(cache, iadr, out, max);
+  hts_mutexlock(&opt->state.lock);
+  cache = hts_cache(opt);
+#if HTS_INET6 != 0
+  hts_resolver_check_env(); /* settle the backend before a worker reads it */
+#endif
+  count = hts_ghbn_all(cache, host, out, max);
+  hts_mutexrelease(&opt->state.lock);
   if (count >= 0) { // cache hit (0 == negative-cached)
     return count;
-  } else { // non présent dans le cache dns, tester
-    SOCaddr resolved[HTS_MAXADDRNUM];
-    t_dnscache *record;
-    int i;
+  }
 
 #if DEBUGDNS
-    printf("resolving (not cached) %s\n", iadr);
+  printf("resolving (not cached) %s\n", host);
 #endif
 
-    count = hts_dns_resolve_nocache_list(iadr, resolved, HTS_MAXADDRNUM, error);
+  /* Resolve with no lock held: getaddrinfo can block for a long time, and
+     state.lock also gates the stop request (#606). */
+  count = hts_dns_resolve_nocache_list_bounded(host, resolved, HTS_MAXADDRNUM,
+                                               opt->timeout, error);
 
 #if HTS_WIDE_DEBUG
-    DEBUG_W("gethostbyname done\n");
+  DEBUG_W("gethostbyname done\n");
 #endif
 
-    /* attempt to store new entry (coucal owns it and dups the host key) */
-    record = malloct(sizeof(t_dnscache));
+  if (count < 0) { /* timed out: no answer to cache, and none to report */
+    if (error != NULL)
+      *error = "host name resolution timed out";
+    return 0;
+  }
+
+  hts_mutexlock(&opt->state.lock);
+  { /* store the full list (coucal owns the record and dups the host key; a
+       concurrent resolve of the same host replaces, and frees, this one) */
+    t_dnscache *const record = malloct(sizeof(t_dnscache));
+
     if (record != NULL) {
       memset(record, 0, sizeof(*record));
       record->host_count = count;
@@ -5137,28 +5251,13 @@ static int hts_dns_resolve_list_(httrackp *opt, const char *_iadr,
         memcpy(record->host_addr[i], &SOCaddr_sockaddr(resolved[i]),
                record->host_length[i]);
       }
-      coucal_add_pvoid(cache, iadr, record);
+      coucal_add_pvoid(cache, host, record);
     }
-
-    /* copy result to caller (cache store may have failed; result still valid)
-     */
-    for (i = 0; i < count && i < max; i++) {
-      SOCaddr_copy_SOCaddr(out[i], resolved[i]);
-    }
-    return count;
-  } // retour hp du cache
-}
-
-int hts_dns_resolve_all(httrackp *opt, const char *iadr, SOCaddr *out, int max,
-                        const char **error) {
-  int count;
-
-  if (!strnotempty(iadr) || max <= 0) {
-    return 0;
   }
-  hts_mutexlock(&opt->state.lock);
-  count = hts_dns_resolve_list_(opt, iadr, out, max, error);
   hts_mutexrelease(&opt->state.lock);
+
+  /* copy result to caller (cache store may have failed; result still valid) */
+  dns_copy_addrs(out, resolved, count, max);
   return count;
 }
 
diff --git a/src/htslib.h b/src/htslib.h
index b059dd75..6bf928c6 100644
--- a/src/htslib.h
+++ b/src/htslib.h
@@ -222,7 +222,8 @@ LLint http_xfread1(htsblk * r, int bufl);
 /* Cached resolver: fill out[0..count-1] with up to max addresses for iadr (in
    resolver order), returning the count (0 = does not resolve, negative-cached).
    Resolves once per host; later calls read the DNS cache. Must hold no lock
-   (brackets opt->state.lock itself). */
+   (brackets opt->state.lock itself, never across the resolve). A miss resolves
+   on a worker thread bounded by opt->timeout; a timeout reports 0, uncached. */
 int hts_dns_resolve_all(httrackp *opt, const char *iadr, SOCaddr *out, int max,
                         const char **error);
 HTS_INLINE SOCaddr *hts_dns_resolve2(httrackp *opt, const char *iadr,
diff --git a/src/htsselftest.c b/src/htsselftest.c
index d8de32f8..5abba57c 100644
--- a/src/htsselftest.c
+++ b/src/htsselftest.c
@@ -2109,6 +2109,15 @@ static int st_dns(httrackp *opt, int argc, char **argv) {
   return err;
 }
 
+static int st_dnstimeout(httrackp *opt, int argc, char **argv) {
+  const int err = dns_timeout_selftests(opt);
+
+  (void) argc;
+  (void) argv;
+  printf("dns-timeout-selftest: %s\n", err ? "FAIL" : "OK");
+  return err;
+}
+
 static int st_cookies(httrackp *opt, int argc, char **argv) {
   static t_cookie cookie;
   char hdr[1024];
@@ -3133,6 +3142,8 @@ static const struct selftest_entry {
     {"cache-corrupt", "<dir>", "cache read-side corruption self-test",
      st_cache_corrupt},
     {"dns", "", "DNS resolver/cache self-test", st_dns},
+    {"dnstimeout", "", "a slow DNS resolve is bounded and holds no lock",
+     st_dnstimeout},
     {"cookies", "", "cookie request-header self-test", st_cookies},
     {"useragent", "", "default User-Agent self-test", st_useragent},
     {"makeindex", "[dir]", "hts_finish_makeindex footer/refresh self-test",
diff --git a/tests/01_engine-dnstimeout.test b/tests/01_engine-dnstimeout.test
new file mode 100644
index 00000000..165761d9
--- /dev/null
+++ b/tests/01_engine-dnstimeout.test
@@ -0,0 +1,15 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# A resolve against a deliberately slow mock getaddrinfo (no network) must
+# return on --timeout, must not hold opt->state.lock meanwhile, and must not
+# cache the timeout as an answer (#606).
+# 'run' is an ignored placeholder argument.
+out=$(httrack -#test=dnstimeout run)
+
+test "$out" = "dns-timeout-selftest: OK" || {
+    echo "expected 'dns-timeout-selftest: OK', got: $out" >&2
+    exit 1
+}
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 39c04bfe..217a7caf 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -35,6 +35,7 @@ TESTS = \
 	01_engine-copyopt.test \
 	01_engine-crange.test \
 	01_engine-dns.test \
+	01_engine-dnstimeout.test \
 	01_engine-doitlog.test \
 	01_engine-entities.test \
 	01_engine-filelist.test \