diff --git a/checksum.c b/checksum.c
index 6f0f95ab..81f18ecf 100644
--- a/checksum.c
+++ b/checksum.c
@@ -36,11 +36,30 @@
 #endif
 
 extern int am_server;
+extern int am_daemon;
+extern int always_checksum;
 extern int whole_file;
 extern int checksum_seed;
 extern int protocol_version;
 extern int proper_seed_order;
 extern const char *checksum_choice;
+extern void maybe_send_keepalive(time_t now, int flags);
+
+static time_t last_checksum_keepalive = 0;
+
+static inline void send_checksum_keepalive(void)
+{
+	time_t now;
+
+	if (!am_daemon || !always_checksum)
+		return;
+
+	now = time(NULL);
+	if (now - last_checksum_keepalive >= 5) {
+		last_checksum_keepalive = now;
+		maybe_send_keepalive(now, MSK_ALLOW_FLUSH);
+	}
+}
 
 #define NNI_BUILTIN (1<<0)
 #define NNI_EVP (1<<1)
@@ -421,8 +440,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		EVP_DigestInit_ex(evp, file_sum_evp_md, NULL);
 
-		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE) {
 			EVP_DigestUpdate(evp, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+			send_checksum_keepalive();
+		}
 
 		remainder = (int32)(len - i);
 		if (remainder > 0)
@@ -440,8 +461,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		XXH64_reset(state, 0);
 
-		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE) {
 			XXH64_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+			send_checksum_keepalive();
+		}
 
 		remainder = (int32)(len - i);
 		if (remainder > 0)
@@ -459,8 +482,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		XXH3_64bits_reset(state);
 
-		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE) {
 			XXH3_64bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+			send_checksum_keepalive();
+		}
 
 		remainder = (int32)(len - i);
 		if (remainder > 0)
@@ -477,8 +502,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		XXH3_128bits_reset(state);
 
-		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE) {
 			XXH3_128bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+			send_checksum_keepalive();
+		}
 
 		remainder = (int32)(len - i);
 		if (remainder > 0)
@@ -495,8 +522,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		md5_begin(&m5);
 
-		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+		for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE) {
 			md5_update(&m5, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+			send_checksum_keepalive();
+		}
 
 		remainder = (int32)(len - i);
 		if (remainder > 0)
@@ -513,8 +542,10 @@ void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 
 		mdfour_begin(&m);
 
-		for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
+		for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
 			mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK), CSUM_CHUNK);
+			send_checksum_keepalive();
+		}
 
 		/* Prior to version 27 an incorrect MD4 checksum was computed
 		 * by failing to call mdfour_tail() for block sizes that