custom SSH port for Borg remote targets

feat(host-backup): custom SSH port for Borg remote targets Add Borg destinations no longer assume port 22. The Monitor form and the shell TUI both take an optional port (default 22, range 1-65535) and embed it in the persisted ssh://user@host:port/path URL. BORG_RSH, the sshpass key installer and the capacity probe all honour it. Reported by @songochain in #236 — NAS-style Borg hosts on non-standard SSH ports are now first-class targets. Existing borg-targets.txt entries without a port keep working; the port is only serialised into the URL when it differs from 22.
2026-09-14 10:47:36 +00:00 · 2026-09-02 14:43:28 +02:00
parent 45cc2ba36e
commit 91b4200179
12 changed files with 187 additions and 29 deletions
@@ -2717,6 +2717,11 @@ interface BorgRepo {
  name: string
  repository: string
  ssh_key_path?: string
+  // Parsed from `ssh://user@host[:port]/path`; 22 for URLs without an
+  // explicit port and 0 for local-mode targets. Newer backends ship
+  // this; older ones don't and the frontend falls back to re-parsing
+  // the URL on the fly.
+  ssh_port?: number
  // Encryption + saved-passphrase metadata. Newer backends ship these;
  // older deployments without the fields default to "repokey" (the
  // shell installer's historical default) and unknown-passphrase.
@@ -6092,6 +6097,11 @@ function AddDestinationDialog({
  const [borgMode, setBorgMode] = useState<"local" | "ssh">("local")
  const [borgSshUser, setBorgSshUser] = useState("borg")
  const [borgSshHost, setBorgSshHost] = useState("")
+  // Custom SSH port for NAS-style hosts that expose SSH on non-22.
+  // Kept as string in state so the input can start empty; converted to
+  // integer at submit time. Empty / "22" means "use the default port"
+  // and is omitted from the ssh:// URL by the backend.
+  const [borgSshPort, setBorgSshPort] = useState("22")
  const [borgSshRemotePath, setBorgSshRemotePath] = useState("")
  const [borgSshKeyPath, setBorgSshKeyPath] = useState("/root/.ssh/proxmenux_borg")
  const [generatedKey, setGeneratedKey] = useState<{ public_key: string; authorized_keys_line: string } | null>(null)
@@ -6148,26 +6158,32 @@ function AddDestinationDialog({
      setUsername(editing.username || "root@pam")
      setFingerprint(editing.fingerprint || "")
      setBorgRepo(""); setBorgMode("local"); setBorgSshUser("borg")
-      setBorgSshHost(""); setBorgSshRemotePath("")
+      setBorgSshHost(""); setBorgSshPort("22"); setBorgSshRemotePath("")
      setBorgSshKeyPath("/root/.ssh/proxmenux_borg")
      setBorgEncryptionEnabled(true); setLocalPath("")
      return
    }
    if (editing && editing.kind === "borg") {
      const repo = editing.repository || ""
-      const ssh = repo.match(/^ssh:\/\/([^@]+)@([^/]+)\/(.+)$/)
+      // Match ssh://user@host[:port]/path — the port group is optional.
+      // Group 3 captures the numeric port when present, group 4 the path.
+      const ssh = repo.match(/^ssh:\/\/([^@]+)@([^/:]+)(?::(\d+))?\/(.+)$/)
      setName(editing.name)
      if (ssh) {
        setBorgMode("ssh")
        setBorgSshUser(ssh[1])
        setBorgSshHost(ssh[2])
-        setBorgSshRemotePath(`/${ssh[3]}`)
+        // Prefer the port already parsed by the backend (ssh_port); fall
+        // back to the URL match; default 22 when neither is set.
+        const port = editing.ssh_port ?? (ssh[3] ? Number(ssh[3]) : 22)
+        setBorgSshPort(String(port || 22))
+        setBorgSshRemotePath(`/${ssh[4]}`)
        setBorgSshKeyPath(editing.ssh_key_path || "/root/.ssh/proxmenux_borg")
        setBorgRepo("")
      } else {
        setBorgMode("local")
        setBorgRepo(repo)
-        setBorgSshUser("borg"); setBorgSshHost(""); setBorgSshRemotePath("")
+        setBorgSshUser("borg"); setBorgSshHost(""); setBorgSshPort("22"); setBorgSshRemotePath("")
        setBorgSshKeyPath("/root/.ssh/proxmenux_borg")
      }
      const mode = editing.encrypt_mode || "repokey"
@@ -6186,6 +6202,7 @@ function AddDestinationDialog({
    setBorgMode("local")
    setBorgSshUser("borg")
    setBorgSshHost("")
+    setBorgSshPort("22")
    setBorgSshRemotePath("")
    setBorgSshKeyPath("/root/.ssh/proxmenux_borg")
    setBorgEncryptionEnabled(true)
@@ -6274,6 +6291,12 @@ function AddDestinationDialog({
          body.ssh_host = borgSshHost.trim()
          body.ssh_remote_path = borgSshRemotePath.trim()
          if (borgSshKeyPath.trim()) body.ssh_key_path = borgSshKeyPath.trim()
+          // Only send port when it's non-default; the backend leaves 22
+          // out of the persisted URL so existing targets stay identical.
+          const portNum = parseInt(borgSshPort.trim(), 10)
+          if (Number.isFinite(portNum) && portNum > 0 && portNum !== 22) {
+            body.ssh_port = portNum
+          }
        }
        const resp = await fetchApi<{ repo?: string }>("/api/host-backups/destinations/borg", {
          method: "POST",
@@ -6409,10 +6432,24 @@ function AddDestinationDialog({
                      {t("backup.destinations.sshUserHelpBefore")} <code className="font-mono">borg serve</code>. {t("backup.destinations.sshUserHelpAfter")} <code className="font-mono">borg</code>, {t("backup.destinations.not")} <code className="font-mono">root</code>.
                    </p>
                  </div>
+                  <div className="grid grid-cols-[1fr_100px] gap-3">
                    <div>
                      <Label htmlFor="borgSshHost">{t("backup.fields.sshHostOrIp")}</Label>
                      <Input id="borgSshHost" value={borgSshHost} onChange={(e) => setBorgSshHost(e.target.value)} className="font-mono mt-1" placeholder="backup.example.com" />
                    </div>
+                    <div>
+                      <Label htmlFor="borgSshPort">{t("backup.fields.sshPort")}</Label>
+                      <Input
+                        id="borgSshPort"
+                        value={borgSshPort}
+                        onChange={(e) => setBorgSshPort(e.target.value.replace(/[^\d]/g, ""))}
+                        className="font-mono mt-1"
+                        placeholder="22"
+                        inputMode="numeric"
+                        maxLength={5}
+                      />
+                    </div>
+                  </div>
                  <div>
                    <Label htmlFor="borgSshPath">{t("backup.fields.remoteRepositoryPath")}</Label>
                    <Input id="borgSshPath" value={borgSshRemotePath} onChange={(e) => setBorgSshRemotePath(e.target.value)} className="font-mono mt-1" placeholder="/backup/borgbackup" />
@@ -355,6 +355,15 @@ function suggestPackageName(name: string) {
    .replace(/^-+|-+$/g, "")
 }

+// The argv editors use a comma-separated display value, while the API stores
+// each argument as an array item. Keep this conversion separate from the text
+// shown in the controlled input: normalising the visible value on every
+// keystroke would remove a newly typed comma or trailing space before the user
+// can enter the next argument.
+function parseArgvInput(value: string): string[] {
+  return value.split(",").map((item) => item.trim()).filter(Boolean)
+}
+
 export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Props) {
  const t = useT()
  const isLightTheme = useIsLightTheme()
@@ -371,6 +380,8 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
  const [detectionNotice, setDetectionNotice] = useState<{ found: boolean; text: string } | null>(null)
  // Editor state
  const [editing, setEditing] = useState<{ appId: string | null; draft: AppConfig } | null>(null)
+  const [binaryArgsInput, setBinaryArgsInput] = useState("")
+  const [commandArgvInput, setCommandArgvInput] = useState("")
  const [saving, setSaving] = useState(false)
  const [testingDetector, setTestingDetector] = useState(false)
  const [detectorTest, setDetectorTest] = useState<DetectorTestResult | null>(null)
@@ -742,6 +753,8 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
        setShowAdvanced(false)
      }
    }
+    setBinaryArgsInput((seed.binary_args || []).join(", "))
+    setCommandArgvInput((seed.command_argv || []).join(", "))
    setEditing({ appId: existing?.id || null, draft: seed })
    setDetectorTest(null)
    setError(null)
@@ -749,6 +762,8 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop

  const closeEditor = () => {
    setEditing(null)
+    setBinaryArgsInput("")
+    setCommandArgvInput("")
    setDetectorTest(null)
    setError(null)
  }
@@ -771,6 +786,8 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
      setSidecar(r)
      setLxcAppsCached(vmid, r, suggestions)
      setEditing(null)
+      setBinaryArgsInput("")
+      setCommandArgvInput("")
      onChange?.()
    } catch (e: any) {
      setError(e?.message || t("vmLxc.appEditor.saveFailed"))
@@ -1241,6 +1258,7 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
                              patch.distribution = t.distribution || ""
                              patch.container_name = t.container_name || ""
                              patch.label = t.label || ""
+                              patch.command_argv = t.command_argv || []
                              patch.installed_regex = t.installed_regex || ""
                              patch.upstream_type = (t as any).upstream_type || (t.repo ? "github" : "")
                              patch.repo = t.repo || ""
@@ -1249,6 +1267,8 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
                              patch.upstream_json_path = (t as any).upstream_json_path || ""
                              patch.docker_image = (t as any).docker_image || ""
                              patch.tag_regex = t.tag_regex || "v?(\\d+\\.\\d+\\.\\d+)"
+                              setBinaryArgsInput((t.binary_args || []).join(", "))
+                              setCommandArgvInput((t.command_argv || []).join(", "))
                              setShowAdvanced(true)
                            }
                            setEditing((prev) => prev ? { ...prev, draft: { ...prev.draft, ...patch } } : prev)
@@ -1713,10 +1733,12 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
                        <Label htmlFor="app-de-args">{t("vmLxc.appEditor.binaryArgsLabel")}</Label>
                        <Input
                          id="app-de-args"
-                          value={(draft.binary_args || []).join(", ")}
-                          onChange={(e) => setField({
-                            binary_args: e.target.value.split(",").map(s => s.trim()).filter(Boolean),
-                          })}
+                          value={binaryArgsInput}
+                          onChange={(e) => {
+                            const value = e.target.value
+                            setBinaryArgsInput(value)
+                            setField({ binary_args: parseArgvInput(value) })
+                          }}
                          placeholder={t("vmLxc.appEditor.binaryArgsPlaceholder")}
                          className="font-mono text-xs"
                        />
@@ -1732,10 +1754,12 @@ export function LxcAppPanel({ vmid, ctIp, onChange, managed, initialData }: Prop
                      <Label htmlFor="app-cmd-argv">{t("vmLxc.appEditor.commandLabel")}</Label>
                      <Input
                        id="app-cmd-argv"
-                        value={(draft.command_argv || []).join(", ")}
-                        onChange={(e) => setField({
-                          command_argv: e.target.value.split(",").map(s => s.trim()).filter(Boolean),
-                        })}
+                        value={commandArgvInput}
+                        onChange={(e) => {
+                          const value = e.target.value
+                          setCommandArgvInput(value)
+                          setField({ command_argv: parseArgvInput(value) })
+                        }}
                        placeholder={t("vmLxc.appEditor.commandPlaceholder")}
                        className="font-mono text-xs"
                      />
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VMs/LXCs",
      "when": "Wann",
      "whenLabel": "Wann",
-      "zfsPools": "ZFS-Pools"
+      "zfsPools": "ZFS-Pools",
+      "sshPort": "SSH-Port"
    },
    "jobs": {
      "attachDescriptionAfter": "Backups.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VMs/LXCs",
      "when": "When",
      "whenLabel": "When",
-      "zfsPools": "ZFS pools"
+      "zfsPools": "ZFS pools",
+      "sshPort": "SSH port"
    },
    "jobs": {
      "attachDescriptionAfter": "backups.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VM/LXC",
      "when": "Cuando",
      "whenLabel": "Cuando",
-      "zfsPools": "grupos ZFS"
+      "zfsPools": "grupos ZFS",
+      "sshPort": "Puerto SSH"
    },
    "jobs": {
      "attachDescriptionAfter": "copias de seguridad.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VM/LXC",
      "when": "Quand",
      "whenLabel": "Quand",
-      "zfsPools": "Pools ZFS"
+      "zfsPools": "Pools ZFS",
+      "sshPort": "Port SSH"
    },
    "jobs": {
      "attachDescriptionAfter": "sauvegardes.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VM/LXC",
      "when": "Quando",
      "whenLabel": "Quando",
-      "zfsPools": "Pool ZFS"
+      "zfsPools": "Pool ZFS",
+      "sshPort": "Porta SSH"
    },
    "jobs": {
      "attachDescriptionAfter": "backup.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VMs/LXCs",
      "when": "Quando",
      "whenLabel": "Quando",
-      "zfsPools": "Conjuntos ZFS"
+      "zfsPools": "Conjuntos ZFS",
+      "sshPort": "Porta SSH"
    },
    "jobs": {
      "attachDescriptionAfter": "cópias de segurança.",
@@ -3962,7 +3962,8 @@
      "vmsLxcs": "VM/LXC",
      "when": "Kedy",
      "whenLabel": "Kedy",
-      "zfsPools": "ZFS pooly"
+      "zfsPools": "ZFS pooly",
+      "sshPort": "SSH port"
    },
    "jobs": {
      "attachDescriptionAfter": "zálohy.",
@@ -3963,7 +3963,8 @@
      "vmsLxcs": "virtuella datorer/LXC:er",
      "when": "När",
      "whenLabel": "När",
-      "zfsPools": "ZFS pooler"
+      "zfsPools": "ZFS pooler",
+      "sshPort": "SSH-port"
    },
    "jobs": {
      "attachDescriptionAfter": "säkerhetskopior.",
@@ -16380,11 +16380,29 @@ def _list_borg_destinations() -> list:
                encrypt_mode = (parts[3] if len(parts) > 3 else '').strip() or 'repokey'
                pass_file = f'{_BACKUP_STATE_DIR}/borg-pass-{name}.txt'
                has_passphrase = os.path.isfile(pass_file)
+                # Parse ssh://user@host[:port]/path so the frontend can
+                # display the port without having to re-parse the URL.
+                # Non-ssh targets (local paths) leave ssh_port at 0.
+                ssh_port = 0
+                if repo.startswith('ssh://'):
+                    after_scheme = repo[len('ssh://'):]
+                    at_split = after_scheme.split('@', 1)
+                    if len(at_split) == 2:
+                        host_and_path = at_split[1]
+                        host_part = host_and_path.split('/', 1)[0]
+                        if ':' in host_part:
+                            try:
+                                ssh_port = int(host_part.rsplit(':', 1)[1])
+                            except (ValueError, IndexError):
+                                ssh_port = 0
+                    if ssh_port == 0:
+                        ssh_port = 22
                targets.append({
                    'name': name,
                    'repository': repo,
                    'ssh_key': ssh_key,
                    'ssh_key_path': ssh_key,
+                    'ssh_port': ssh_port,
                    'encrypt_mode': encrypt_mode,
                    'has_passphrase': has_passphrase,
                    'jobs_using': _jobs_using_borg(repo),
@@ -16649,15 +16667,21 @@ def _capacity_local(path: str) -> dict:
    }


-def _capacity_borg_ssh(host: str, user: str, remote_path: str, key_path: str = '') -> dict:
+def _capacity_borg_ssh(host: str, user: str, remote_path: str, key_path: str = '',
+                        port: int = 22) -> dict:
    """Run `df -B1 --output=size,used,avail` over ssh against the
    remote borg repo path. Times out fast — failure is just rendered
-    as a missing capacity badge in the UI, not a hard error."""
+    as a missing capacity badge in the UI, not a hard error.
+
+    ``port`` defaults to 22 (standard SSH); pass a different value for
+    NAS-style hosts that expose SSH on a custom port."""
    if not host or not user or not remote_path:
        return {'error': 'incomplete ssh target'}
    ssh_target = f'{user}@{host}'
    cmd = ['ssh', '-o', 'BatchMode=yes', '-o', 'ConnectTimeout=5',
           '-o', 'StrictHostKeyChecking=accept-new']
+    if port and port != 22:
+        cmd += ['-p', str(int(port))]
    if key_path:
        cmd += ['-i', key_path]
    cmd += [ssh_target, f'df -B1 --output=size,used,avail {shlex.quote(remote_path)}']
@@ -18017,11 +18041,17 @@ def api_host_backups_dest_capacity():
        if kind == 'local' or kind == 'borg-local':
            cap = _capacity_local((t.get('path') or '').strip())
        elif kind == 'borg-ssh':
+            port_raw = t.get('port')
+            try:
+                port = int(port_raw) if port_raw not in (None, '', 0, '0') else 22
+            except (TypeError, ValueError):
+                port = 22
            cap = _capacity_borg_ssh(
                (t.get('host') or '').strip(),
                (t.get('user') or '').strip(),
                (t.get('remote_path') or '').strip(),
                (t.get('key_path') or '').strip(),
+                port=port,
            )
        elif kind == 'pbs':
            cap = _capacity_pbs(
@@ -19219,7 +19249,23 @@ def api_host_backups_dest_borg_add():
        rpath = (payload.get('ssh_remote_path') or '').strip().lstrip('/')
        if not user or not host or not rpath:
            return jsonify({'error': 'ssh_user, ssh_host and ssh_remote_path are required for ssh mode'}), 400
+        # Optional custom SSH port — NAS-style hosts often expose SSH on
+        # a non-standard port to reduce noise from bots. Empty / missing
+        # means default 22, which we leave out of the URL so existing
+        # targets stay byte-identical to how the shell installer writes them.
+        raw_port = payload.get('ssh_port')
+        ssh_port = 22
+        if raw_port not in (None, '', 0, '0'):
+            try:
+                ssh_port = int(raw_port)
+            except (TypeError, ValueError):
+                return jsonify({'error': 'ssh_port must be an integer between 1 and 65535'}), 400
+            if not (1 <= ssh_port <= 65535):
+                return jsonify({'error': 'ssh_port must be an integer between 1 and 65535'}), 400
+        if ssh_port == 22:
            repo = f'ssh://{user}@{host}/{rpath}'
+        else:
+            repo = f'ssh://{user}@{host}:{ssh_port}/{rpath}'
        ssh_key = (payload.get('ssh_key_path') or '').strip()
    elif mode == 'local':
        repo = (payload.get('repo') or '').strip()
@@ -2163,6 +2163,12 @@ hb_borg_generate_and_install_key() {
    local borg_user="$1" host="$2" rpath="$3" mode="$4"
    local _out_var="$5"
    local -n _out_ref="$_out_var"
+    # Custom SSH port arrives via env var so the callers (this file
+    # itself, in 7+ places) don't have to change their signature. When
+    # unset or 22, ssh uses its default and no `-p` flag is injected.
+    local _port="${HB_BORG_INSTALL_PORT:-22}"
+    local _p_flag=()
+    [[ "$_port" != "22" ]] && _p_flag=(-p "$_port")

    local key_file="$HOME/.ssh/borg_proxmenux_$(echo "$host" | tr './:' '___')_ed25519"
    local pub_file="${key_file}.pub"
@@ -2346,6 +2352,7 @@ hb_borg_generate_and_install_key() {
        -o StrictHostKeyChecking=accept-new \
        -o PreferredAuthentications=password -o PubkeyAuthentication=no \
        -o NumberOfPasswordPrompts=1 -o ConnectTimeout=10 \
+        "${_p_flag[@]}" \
        "$admin_user@$host" "true" 2>&1) || true
    if echo "$_probe" | grep -qiE "permission denied[[:space:]]*\(publickey"; then
        # SSH password auth refused by the server — common when the Borg
@@ -2402,6 +2409,7 @@ hb_borg_generate_and_install_key() {
    local push_rc
    SSHPASS="$admin_pass" sshpass -e ssh -o StrictHostKeyChecking=accept-new \
        -o PreferredAuthentications=password -o PubkeyAuthentication=no \
+        "${_p_flag[@]}" \
        "$admin_user@$host" "$install_cmd" <<<"$authorized_line" >/tmp/proxmenux-borg-keypush.log 2>&1
    push_rc=$?

@@ -2509,6 +2517,22 @@ hb_configure_borg_manual() {
                12 78 "borg" 3>&1 1>&2 2>&3) || return 1
            host=$(dialog --backtitle "ProxMenux" --inputbox "$(hb_translate "SSH host or IP:")" \
                "$HB_UI_INPUT_H" "$HB_UI_INPUT_W" "" 3>&1 1>&2 2>&3) || return 1
+            # Custom SSH port (defaults to 22). NAS-style hosts often
+            # move SSH off 22 to keep their intrusion warnings quiet.
+            # Accepted range: 1-65535; anything else re-prompts.
+            local port
+            while :; do
+                port=$(dialog --backtitle "ProxMenux" \
+                    --inputbox "$(hb_translate "SSH port (default 22):")" \
+                    "$HB_UI_INPUT_H" "$HB_UI_INPUT_W" "22" 3>&1 1>&2 2>&3) || return 1
+                port="${port//[[:space:]]/}"
+                [[ -z "$port" ]] && port=22
+                if [[ "$port" =~ ^[0-9]+$ ]] && (( port >= 1 && port <= 65535 )); then
+                    break
+                fi
+                dialog --backtitle "ProxMenux" \
+                    --msgbox "$(hb_translate "Port must be a number between 1 and 65535.")" 8 60
+            done
            rpath=$(dialog --backtitle "ProxMenux" \
                --inputbox "$(hb_translate "Remote repository path:")" \
                "$HB_UI_INPUT_H" "$HB_UI_INPUT_W" "/backup/borgbackup" \
@@ -2598,7 +2622,12 @@ hb_configure_borg_manual() {
                    fi
                    ;;
                generate-auto|generate-manual|generate-pct)
-                    if ! hb_borg_generate_and_install_key "$user" "$host" "$rpath" "$key_mode" ssh_key; then
+                    # Thread the custom port to the key-install helper
+                    # via env var so the sshpass probe and the actual
+                    # push both hit the right port on the Borg server.
+                    HB_BORG_INSTALL_PORT="${port:-22}" \
+                        hb_borg_generate_and_install_key "$user" "$host" "$rpath" "$key_mode" ssh_key
+                    if (( $? != 0 )); then
                        return 1
                    fi
                    ;;
@@ -2606,7 +2635,15 @@ hb_configure_borg_manual() {
                    ssh_key=""
                    ;;
            esac
+            # Custom SSH port is embedded in the URL — Borg's ssh://
+            # scheme natively supports `ssh://user@host:port/path`. Port
+            # 22 is left out for backwards compatibility with existing
+            # borg-targets.txt entries that never carried the port.
+            if [[ "${port:-22}" == "22" ]]; then
                repo="ssh://$user@$host/$rpath"
+            else
+                repo="ssh://$user@$host:$port/$rpath"
+            fi
            ;;
    esac

@@ -2635,7 +2672,13 @@ hb_configure_borg_manual() {

    _borg_repo_ref_new="$repo"
    if [[ -n "$ssh_key" ]]; then
-        export BORG_RSH="ssh -i $ssh_key -o StrictHostKeyChecking=accept-new"
+        local rsh_cmd="ssh -i $ssh_key -o StrictHostKeyChecking=accept-new"
+        [[ -n "${port:-}" && "$port" != "22" ]] && rsh_cmd="$rsh_cmd -p $port"
+        export BORG_RSH="$rsh_cmd"
+    elif [[ -n "${port:-}" && "$port" != "22" ]]; then
+        # No custom key but non-default port — still need to tell ssh
+        # which port to hit so `borg` doesn't fall back to 22.
+        export BORG_RSH="ssh -o StrictHostKeyChecking=accept-new -p $port"
    else
        unset BORG_RSH
    fi