diff --git a/irc/config.go b/irc/config.go
index c01bffca..42be0a1d 100644
--- a/irc/config.go
+++ b/irc/config.go
@@ -827,11 +827,6 @@ func LoadConfig(filename string) (config *Config, err error) {
 
 	config.loadMOTD()
 
-	err = config.generateISupport()
-	if err != nil {
-		return nil, err
-	}
-
 	// in the current implementation, we disable history by creating a history buffer
 	// with zero capacity. but the `enabled` config option MUST be respected regardless
 	// of this detail
@@ -847,5 +842,11 @@ func LoadConfig(filename string) (config *Config, err error) {
 		}
 	}
 
+	// now that all postprocessing is complete, regenerate ISUPPORT:
+	err = config.generateISupport()
+	if err != nil {
+		return nil, err
+	}
+
 	return config, nil
 }
diff --git a/irc/server.go b/irc/server.go
index c5c78d34..b9a79536 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -42,6 +42,10 @@ var (
 	// whitelist of caps to serve on the STS-only listener. In particular,
 	// never advertise SASL, to discourage people from sending their passwords:
 	stsOnlyCaps = caps.NewSet(caps.STS, caps.MessageTags, caps.ServerTime, caps.LabeledResponse, caps.Nope)
+
+	// we only have standard channels for now. TODO: any updates to this
+	// will also need to be reflected in CasefoldChannel
+	chanTypes = "#"
 )
 
 // ListenerWrapper wraps a listener so it can be safely reconfigured or stopped
@@ -137,12 +141,13 @@ func (config *Config) generateISupport() (err error) {
 	isupport.Initialize()
 	isupport.Add("AWAYLEN", strconv.Itoa(config.Limits.AwayLen))
 	isupport.Add("CASEMAPPING", "ascii")
+	isupport.Add("CHANLIMIT", fmt.Sprintf("%s:%d", chanTypes, config.Channels.MaxChannelsPerClient))
 	isupport.Add("CHANMODES", strings.Join([]string{modes.Modes{modes.BanMask, modes.ExceptMask, modes.InviteMask}.String(), "", modes.Modes{modes.UserLimit, modes.Key}.String(), modes.Modes{modes.InviteOnly, modes.Moderated, modes.NoOutside, modes.OpOnlyTopic, modes.ChanRoleplaying, modes.Secret}.String()}, ","))
 	if config.History.Enabled && config.History.ChathistoryMax > 0 {
 		isupport.Add("draft/CHATHISTORY", strconv.Itoa(config.History.ChathistoryMax))
 	}
 	isupport.Add("CHANNELLEN", strconv.Itoa(config.Limits.ChannelLen))
-	isupport.Add("CHANTYPES", "#")
+	isupport.Add("CHANTYPES", chanTypes)
 	isupport.Add("ELIST", "U")
 	isupport.Add("EXCEPTS", "")
 	isupport.Add("INVEX", "")