fix(ui): stop split DNS from crashing the page when undefined

Closes HP-548.

CHANGELOG.md

@@ -10,6 +10,7 @@
 - Fixed OIDC token exchange fallback when retrying with `client_secret_basic` (closes [#493](https://github.com/tale/headplane/issues/493)).
 - Added support for proxy authentication via `server.proxy_auth` (closes [#353](https://github.com/tale/headplane/issues/353)).
 - Added automatic role assignment for new OIDC users via `oidc.default_role` and IdP-provided role claims via `oidc.role_claim` (closes [#352](https://github.com/tale/headplane/issues/352)).
+- Fixed the DNS page crashing when Headscale has no Split DNS nameservers configured (closes [#570](https://github.com/tale/headplane/issues/570)).
 
 ---
 

app/server/headscale/config-loader.ts

@@ -193,7 +193,7 @@ function getDNSConfig(config: HeadscaleConfigState): DNSConfigView {
     magicDns: dns.magic_dns,
     baseDomain: dns.base_domain,
     nameservers: dns.nameservers.global,
-    splitDns: dns.nameservers.split,
+    splitDns: dns.nameservers.split ?? {},
     searchDomains: dns.search_domains,
     overrideDns: dns.override_local_dns,
     extraRecords: dnsRecords(config),