Some types of audit event samples from [our documentation](https://www.elastic.co/guide/en/elasticsearch/reference/7.17/audit-event-types.html) include the port number in "origin.address", like **access_denied**:
```json
{"type":"audit", "timestamp":"2020-12-30T22:30:06,949+0200", "node.id":
"0RMNyghkQYCc_gVd1G6tZQ", "event.type":"transport", "event.action":
"access_denied", "authentication.type":"REALM", "user.name":"user1",
"user.realm":"default_native", "user.roles":["test_role"], "origin.type":
"rest", "origin.address":"[::1]:52434", "request.id":"yKOgWn2CRQCKYgZRz3phJw",
"action":"indices:admin/auto_create", "request.name":"CreateIndexRequest",
"indices":["<index-{now/d+1d}>"]}
```
but other types like **connection_denied** from this issue does not include the port:

```json
{"type":"audit", "timestamp":"2020-12-30T21:47:31,526+0200", "node.id":
"0RMNyghkQYCc_gVd1G6tZQ", "event.type":"ip_filter", "event.action":
"connection_denied", "origin.type":"rest", "origin.address":"10.10.0.20",
"transport.profile":".http", "rule":"deny 10.10.0.0/16"}
```

I think we should be consistent here and always include the port number in the "origin.address" field.
x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/transport/filter/IPFilterTests.java
for (String inetAddress : inetAddresses) {
            String message = String.format(Locale.ROOT, "Expected address %s to be denied", inetAddress);
            InetAddress address = InetAddresses.forString(inetAddress);
            assertFalse(message, ipFilter.accept(profile, new InetSocketAddress(address, 0)));
            ArgumentCaptor<SecurityIpFilterRule> ruleCaptor = ArgumentCaptor.forClass(SecurityIpFilterRule.class);
            verify(auditTrail).connectionDenied(eq(address), eq(profile), ruleCaptor.capture());
            assertNotNull(ruleCaptor.getValue());
        }
    }
    private void assertAddressIsDenied(String... inetAddresses) {
        assertAddressIsDeniedForProfile("default", inetAddresses);
    }
    private String randomNonLocalIPv4Address() throws SocketException, UnknownHostException {
        String ipv4Address = null;
        int noOfRetries = 0;
        do {
            noOfRetries++;
            final InetAddress address = InetAddress.getByAddress(Numbers.intToBytes(randomInt()));
            if (address.isAnyLocalAddress() || address.isLoopbackAddress() || NetworkInterface.getByInetAddress(address) != null) {
                continue;
            } else {
                ipv4Address = NetworkAddress.format(address);
                break;
            }
        } while (ipv4Address == null && noOfRetries < 25);
        assertThat("could not generate random IPv4 address which is not local address", ipv4Address, notNullValue());
        return ipv4Address;
    }
}