Name
-d8.1
Synopsis
Name resolution is the process of determining a machine’s IP address based on its fully qualified domain name. This is done by using the Domain Name System (DNS). The process that sendmail uses to resolve a name is described in Section 9.2.
When sendmail finds that a hostname is really an
MX record, it attempts to look up the address (which can be an A or
AAAA record) for the host that handles mail receipt. That request can
fail for a variety of reasons. If the -d8.1
(a.k.a. -d8
) debugging switch is specified,
sendmail produces the following message:
getmxrr: res_search(host) failed (errno=errornum, h_errno=herrornum)
Here, host is the hostname that was looked up, errornum is the system error number (if any) from <errno.h>, and herrornum is the resolver-specific error number from <netdb.h>, as shown in Table 16-7.
Value |
Mnemonic |
Description |
-1 |
NETDB_INTERNAL |
Error in the lookup code, see |
0 |
NETDB_SUCCESS |
Success |
1 |
HOST_NOT_FOUND |
Host not found |
2 |
TRY_AGAIN |
Temporary DNS server failure |
3 |
NO_RECOVERY |
Nonrecoverable errors and refusals |
4 |
NO_DATA |
Valid name but no record of requested type |
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