diff --git a/crates/kumo-spf/src/lib.rs b/crates/kumo-spf/src/lib.rs
index 0e2ec4d6..333c93d6 100644
--- a/crates/kumo-spf/src/lib.rs
+++ b/crates/kumo-spf/src/lib.rs
@@ -177,7 +177,7 @@ impl<'a> SpfContext<'a> {
     }
 
     pub async fn check(&self, resolver: &dyn Resolver, initial: bool) -> SpfResult {
-        let name = match Name::from_utf8(self.domain) {
+        let name = match Name::from_str_relaxed(self.domain) {
             Ok(name) => name,
             Err(_) => {
                 // Per <https://www.rfc-editor.org/rfc/rfc7208#section-4.3>, invalid
diff --git a/crates/kumo-spf/src/record.rs b/crates/kumo-spf/src/record.rs
index 6fcaf6e6..cf58addc 100644
--- a/crates/kumo-spf/src/record.rs
+++ b/crates/kumo-spf/src/record.rs
@@ -4,7 +4,6 @@ use dns_resolver::Resolver;
 use hickory_resolver::Name;
 use std::fmt;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
-use std::str::FromStr;
 
 #[derive(Debug, Default)]
 pub(crate) struct Record {
@@ -229,7 +228,7 @@ impl Directive {
             }
             .matches(cx.client_ip, IpAddr::V6(*ip6_network)),
             Mechanism::Ptr { domain } => {
-                let domain = match Name::from_str(&cx.domain(domain.as_ref())?) {
+                let domain = match Name::from_str_relaxed(&cx.domain(domain.as_ref())?) {
                     Ok(domain) => domain,
                     Err(err) => {
                         return Err(SpfResult {
diff --git a/crates/kumo-spf/src/tests.rs b/crates/kumo-spf/src/tests.rs
index 9018c476..1d57c7ba 100644
--- a/crates/kumo-spf/src/tests.rs
+++ b/crates/kumo-spf/src/tests.rs
@@ -124,6 +124,30 @@ async fn mx() {
     );
 }
 
+#[tokio::test]
+async fn underscores() {
+    let resolver = TestResolver::default()
+        .with_zone(EXAMPLE_COM)
+        .with_txt(
+            "under_score.com",
+            "v=spf1 ip4:192.0.2.128/28 -all".to_string(),
+        )
+        .with_txt(
+            "example.com",
+            "v=spf1 include:under_score.com -all".to_string(),
+        );
+
+    let result = evaluate_ip(Ipv4Addr::from([192, 0, 2, 65]), &resolver).await;
+    k9::assert_equal!(
+        &result,
+        &SpfResult {
+            disposition: SpfDisposition::Fail,
+            context: "matched '-all' directive".to_owned(),
+        },
+        "{result:?}"
+    );
+}
+
 /// https://www.rfc-editor.org/rfc/rfc7208#appendix-A.1
 #[tokio::test]
 async fn ip4() {