On 10/15/20 10:13 PM, Aki Tuomi wrote: >> I'm asking how/where to 'tell', via config, Dovecot's smtp-CLIENT, that's >> making to connection to the submission_relay_host, to use _only_ IPv4. > > There is currently no (other) way to do this than using /etc/hosts or > specifying IPv4 address for the relay host.
just a quick look, but looks like the culprit here is the submission code call
to "net_addr2ip()"
src/submission/main.c (c)
...
193 static void main_stdio_run(const char *username)
{
struct mail_storage_service_input input;
buffer_t *input_buf;
const char *value, *error, *input_base64;
i_zero(&input);
input.module = input.service = "submission";
input.username = username != NULL ? username :
getenv("USER");
if (input.username == NULL && IS_STANDALONE())
input.username = getlogin();
if (input.username == NULL)
i_fatal("USER environment missing");
if ((value = getenv("IP")) != NULL)
!!! (void)net_addr2ip(value,
&input.remote_ip);
if ((value = getenv("LOCAL_IP")) != NULL)
(void)net_addr2ip(value,
&input.local_ip);
input_base64 = getenv("CLIENT_INPUT");
input_buf = input_base64 == NULL ? NULL :
t_base64_decode_str(input_base64);
if (client_create_from_input(&input,
STDIN_FILENO, STDOUT_FILENO,
input_buf,
&error) < 0)
i_fatal("%s", error);
}
...
which includes ipv6-first code,
./src/lib/net.c
...
932 int net_addr2ip(const char *addr, struct ip_addr *ip)
{
int ret;
if (net_addr2ip_inet4_fast(addr, ip))
return 0;
if (strchr(addr, ':') != NULL) {
!!! /* IPv6 */
T_BEGIN {
if (addr[0] == '[') {
/* allow [ipv6 addr] */
size_t len =
strlen(addr);
if (addr[len-1] == ']')
addr =
t_strndup(addr+1, len-2);
}
ret = inet_pton(AF_INET6, addr,
&ip->u.ip6);
} T_END;
if (ret == 0)
return -1;
ip->family = AF_INET6;
} else {
/* IPv4 */
if (inet_aton(addr, &ip->u.ip4) == 0)
return -1;
ip->family = AF_INET;
}
return 0;
}
...
adding a config param, e.g.,
submission_relay_ip_family = {any:inet6:inet4}
and wrapping the "src/lib/net.c" stanza, above, in 'if' conditionals based on
its value
should, iiuc, sufficiently instruct Dovecot to relay-submit over the intended
AF.
and stop causing the 'failed connect' error noise in logs.
