https://bugs.exim.org/show_bug.cgi?id=2855#c4
--- a/src/src/spool_out.c
+++ b/src/src/spool_out.c
@@ -185,7 +185,7 @@ if (sender_helo_name) spool_var_write(fp, US"helo_name", sender_helo_name);
if (sender_host_address)
{
if (is_tainted(sender_host_address)) putc('-', fp);
- fprintf(fp, "-host_address %s.%d\n", sender_host_address, sender_host_port);
+ fprintf(fp, "-host_address [%s]:%d\n", sender_host_address, sender_host_port);
if (sender_host_name)
spool_var_write(fp, US"host_name", sender_host_name);
}
is a possible fix, but needs to pass the testsuite
