diff --git a/src/channels.rs b/src/channels.rs
index 8e3070e..a45845e 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -906,6 +906,9 @@ impl Server {
                     Some(b'y') => {
                         crate::modules::reputation::score_ban_match(self, uid, &b.mask[2..])
                     }
+                    Some(b'r') => crate::modules::realnameban::matches(self, uid, &b.mask[2..]),
+                    Some(b'j') => crate::modules::channelban::matches(self, uid, &b.mask[2..]),
+                    Some(b's') => crate::modules::serverban::matches(self, uid, &b.mask[2..]),
                     _ => false,
                 }
             } else {
@@ -1114,8 +1117,10 @@ pub fn normalize_mask(m: &str) -> String {
 pub fn normalize_ban_mask(m: &str) -> String {
     let b = m.as_bytes();
     if b.len() >= 2 && b[1] == b':' && (b[0] as char).is_ascii_alphabetic() {
-        // g: (security-group name) and y: (reputation score spec) aren't host masks
-        if b[0] == b'g' || b[0] == b'y' {
+        // These extbans carry a name / spec / channel / server, not a host mask,
+        // so they must not be host-normalised: g: (security group), y: (reputation
+        // score), r: (realname), j: (channel), s: (server name).
+        if matches!(b[0], b'g' | b'y' | b'r' | b'j' | b's') {
             return m.to_string();
         }
         return format!("{}:{}", &m[..1], normalize_mask(&m[2..]));
diff --git a/src/modules/channelban.rs b/src/modules/channelban.rs
new file mode 100644
index 0000000..d07f324
--- /dev/null
+++ b/src/modules/channelban.rs
@@ -0,0 +1,47 @@
+//! channelban — the `j:` matching extban: match a user by another channel they
+//! are in. `+b j:#lobby` bans everyone who is also in `#lobby`; an optional status
+//! prefix narrows it to members at/above that rank, e.g. `+b j:@#staff` matches
+//! only ops-or-higher in `#staff`. The channel part is a glob. Dispatched from the
+//! channel ban matcher; the logic lives here in its own file.
+//!
+//! Behaviour reference: InspIRCd's `m_channelban`. Original native Rust.
+
+use crate::channels::{glob_match, RANK_ADMIN, RANK_HALFOP, RANK_OP, RANK_OWNER, RANK_VOICE};
+use crate::server::Server;
+use crate::Uid;
+
+/// Map a leading status prefix to the minimum rank it requires; `None` if the
+/// first char isn't a prefix (so the whole string is the channel glob).
+fn split_prefix(mask: &str) -> (u8, &str) {
+    match mask.chars().next() {
+        Some('~') => (RANK_OWNER, &mask[1..]),
+        Some('&') => (RANK_ADMIN, &mask[1..]),
+        Some('@') => (RANK_OP, &mask[1..]),
+        Some('%') => (RANK_HALFOP, &mask[1..]),
+        Some('+') => (RANK_VOICE, &mask[1..]),
+        _ => (0, mask),
+    }
+}
+
+/// Is `uid` a member (at/above the required rank) of a channel matching the glob
+/// in `mask` (the part after `j:`)?
+pub fn matches(s: &Server, uid: Uid, mask: &str) -> bool {
+    let (min_rank, changlob) = split_prefix(mask);
+    let changlob = changlob.to_ascii_lowercase();
+    let Some(u) = s.users.get(&uid) else {
+        return false;
+    };
+    u.channels.iter().any(|key| {
+        if !glob_match(&changlob, key) {
+            return false;
+        }
+        if min_rank == 0 {
+            return true;
+        }
+        s.channels
+            .get(key)
+            .and_then(|ch| ch.members.get(&uid))
+            .map(|m| m.rank() >= min_rank)
+            .unwrap_or(false)
+    })
+}
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index 47c5c13..527fb01 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -6,6 +6,7 @@
 pub mod antimixedutf8;
 pub mod antirandom;
 pub mod blockamsg;
+pub mod channelban;
 pub mod chathistory;
 pub mod cloak;
 pub mod connectban;
@@ -19,10 +20,12 @@ pub mod metadata;
 pub mod multiline;
 pub mod network_icon;
 pub mod profilelink;
+pub mod realnameban;
 pub mod reputation;
 pub mod restrictcommands;
 pub mod restrictmsg;
 pub mod securitygroups;
+pub mod serverban;
 pub mod snoop;
 pub mod whoisport;
 
diff --git a/src/modules/realnameban.rs b/src/modules/realnameban.rs
new file mode 100644
index 0000000..5dc6046
--- /dev/null
+++ b/src/modules/realnameban.rs
@@ -0,0 +1,18 @@
+//! realnameban — the `r:` matching extban: match a user by their real name
+//! (GECOS) instead of their host. `+b r:*some spammer*` bans everyone whose
+//! realname matches the glob. Dispatched from the channel ban matcher; the logic
+//! lives here in its own file.
+//!
+//! Behaviour reference: InspIRCd's `m_realnameban`. Original native Rust.
+
+use crate::channels::glob_match;
+use crate::server::Server;
+use crate::Uid;
+
+/// Does `uid`'s realname match the glob `mask` (the part after `r:`)?
+pub fn matches(s: &Server, uid: Uid, mask: &str) -> bool {
+    s.users
+        .get(&uid)
+        .map(|u| glob_match(mask, &u.realname))
+        .unwrap_or(false)
+}
diff --git a/src/modules/serverban.rs b/src/modules/serverban.rs
new file mode 100644
index 0000000..ef5418d
--- /dev/null
+++ b/src/modules/serverban.rs
@@ -0,0 +1,20 @@
+//! serverban — the `s:` matching extban: match a user by the name of the server
+//! they are connected to. `+b s:irc.example.net` bans everyone on that server.
+//! Ban matching only ever runs against local users (join happens locally), so a
+//! matched user is on this server — we glob the mask against our own name.
+//! Dispatched from the channel ban matcher; the logic lives here.
+//!
+//! Behaviour reference: InspIRCd's `m_serverban`. Original native Rust.
+
+use crate::channels::glob_match;
+use crate::server::Server;
+use crate::Uid;
+
+/// Does `uid`'s server name match the glob `mask` (the part after `s:`)?
+pub fn matches(s: &Server, uid: Uid, mask: &str) -> bool {
+    // local users are on this server; guard on the user still existing
+    if !s.users.contains_key(&uid) {
+        return false;
+    }
+    glob_match(mask, &s.name)
+}
diff --git a/src/users.rs b/src/users.rs
index 7a23cfe..0af54d9 100644
--- a/src/users.rs
+++ b/src/users.rs
@@ -449,7 +449,7 @@ impl Server {
             uid,
             RPL_ISUPPORT,
             &format!(
-                "CHANTYPES=# PREFIX=(qaohv)~&@%+ CHANMODES=beIgX,k,lfjFLHBJdK,ACDGMNOPQRSTUcimnpstuz EXTBAN=,cgmny WATCH=128 MONITOR=128 SILENCE=32 CALLERID=g WHOX CHATHISTORY=256 MSGREFTYPES=timestamp,msgid UTF8ONLY CASEMAPPING=ascii NICKLEN=30 CHANNELLEN=50 NETWORK={} :are supported by this server",
+                "CHANTYPES=# PREFIX=(qaohv)~&@%+ CHANMODES=beIgX,k,lfjFLHBJdK,ACDGMNOPQRSTUcimnpstuz EXTBAN=,cgjmnrsy WATCH=128 MONITOR=128 SILENCE=32 CALLERID=g WHOX CHATHISTORY=256 MSGREFTYPES=timestamp,msgid UTF8ONLY CASEMAPPING=ascii NICKLEN=30 CHANNELLEN=50 NETWORK={} :are supported by this server",
                 self.network
             ),
         );