Implement custom dns servers

src/components/proxy-hosts/DnsResolverFields.tsx

@@ -0,0 +1,85 @@
+import { Box, Collapse, Stack, Switch, TextField, Typography, Alert } from "@mui/material";
+import { useState } from "react";
+import { ProxyHost } from "@/src/lib/models/proxy-hosts";
+
+export function DnsResolverFields({
+  dnsResolver
+}: {
+  dnsResolver?: ProxyHost["dns_resolver"] | null;
+}) {
+  const initial = dnsResolver ?? null;
+  const [enabled, setEnabled] = useState(initial?.enabled ?? false);
+
+  return (
+    <Box
+      sx={{
+        borderRadius: 2,
+        border: "1px solid",
+        borderColor: "warning.main",
+        bgcolor: "rgba(237, 108, 2, 0.05)",
+        p: 2.5
+      }}
+    >
+      <input type="hidden" name="dns_present" value="1" />
+      <input type="hidden" name="dns_enabled_present" value="1" />
+      <Stack spacing={2}>
+        <Stack direction="row" alignItems="center" justifyContent="space-between">
+          <Box>
+            <Typography variant="subtitle1" fontWeight={600}>
+              Custom DNS Resolvers
+            </Typography>
+            <Typography variant="body2" color="text.secondary">
+              Configure per-host DNS resolution for upstream discovery and health checks
+            </Typography>
+          </Box>
+          <Switch
+            name="dns_enabled"
+            checked={enabled}
+            onChange={(_, checked) => setEnabled(checked)}
+          />
+        </Stack>
+
+        <Collapse in={enabled} timeout="auto" unmountOnExit>
+          <Stack spacing={2.5}>
+            <TextField
+              name="dns_resolvers"
+              label="DNS Resolvers"
+              placeholder={"1.1.1.1\n8.8.8.8"}
+              defaultValue={initial?.resolvers?.join("\n") ?? ""}
+              helperText="One resolver per line (e.g., 1.1.1.1, 8.8.8.8). Used for dynamic upstream DNS resolution."
+              multiline
+              minRows={2}
+              fullWidth
+              size="small"
+            />
+            <TextField
+              name="dns_fallbacks"
+              label="Fallback DNS Resolvers (Optional)"
+              placeholder={"8.8.4.4\n1.0.0.1"}
+              defaultValue={initial?.fallbacks?.join("\n") ?? ""}
+              helperText="Fallback resolvers if primary fails. One per line."
+              multiline
+              minRows={2}
+              fullWidth
+              size="small"
+            />
+            <TextField
+              name="dns_timeout"
+              label="DNS Query Timeout"
+              placeholder="5s"
+              defaultValue={initial?.timeout ?? ""}
+              helperText="Timeout for DNS queries (e.g., 5s, 10s)"
+              fullWidth
+              size="small"
+            />
+            <Alert severity="info">
+              Per-host DNS resolvers override global settings for this specific proxy host.
+              Useful for upstream services that require specific DNS resolution (e.g., internal DNS, service discovery).
+              Common resolvers: 1.1.1.1 (Cloudflare), 8.8.8.8 (Google), 9.9.9.9 (Quad9).
+            </Alert>
+          </Stack>
+        </Collapse>
+      </Stack>
+    </Box>
+  );
+}

src/components/proxy-hosts/HostDialogs.tsx

@@ -14,6 +14,7 @@ import { ProxyHost } from "@/src/lib/models/proxy-hosts";
 import { AuthentikSettings } from "@/src/lib/settings";
 import { AppDialog } from "@/src/components/ui/AppDialog";
 import { AuthentikFields } from "./AuthentikFields";
+import { DnsResolverFields } from "./DnsResolverFields";
 import { LoadBalancerFields } from "./LoadBalancerFields";
 import { SettingsToggles } from "./SettingsToggles";
 import { UpstreamInput } from "./UpstreamInput";
@@ -122,6 +123,7 @@ export function CreateHostDialog({
                 />
                 <AuthentikFields defaults={authentikDefaults} authentik={initialData?.authentik} />
                 <LoadBalancerFields loadBalancer={initialData?.load_balancer} />
+                <DnsResolverFields dnsResolver={initialData?.dns_resolver} />
             </Stack>
         </AppDialog>
     );
@@ -217,6 +219,7 @@ export function EditHostDialog({
                 />
                 <AuthentikFields authentik={host.authentik} />
                 <LoadBalancerFields loadBalancer={host.load_balancer} />
+                <DnsResolverFields dnsResolver={host.dns_resolver} />
             </Stack>
         </AppDialog>
     );