XCON: Check DNS When Receiving Event ID 9318 with Windows NT Error 1722


In the versions of Microsoft Exchange Server listed at the beginning of this article, you may experience some or all of the following symptoms:
  • Mail backs up between one of the servers in a site and all of the other servers in the site.
  • Numerous instances of the following warning event may be logged:
    Event ID: 9318
    Source: MSExchangeMTA
    Type: Warning
    Category: Interface Description
    An RPC communications error occurred.
    Unable to bind over RPC. The locality table (LTAB) index is 76.
    Windows NT error code: 1722. [BASE IL MAIN BASE 1 500] (12)
  • If you ping by IP, the ping is successful.
  • If you ping by server name, the ping may be successful at times and unsuccessful at other times.
  • RPC ping does not work in one direction. It works from the answering server, but it does not work from the calling server to the answering server.
  • If you restart the server, you temporarily resolve the issue. However, after a period of time, mail flow stops again on the server.


This behavior can occur if there are two Domain Name System (DNS) servers selected in the TCP/IP stack on the server, and the second DNS server points to a server that is still on the network, but which is no longer being used for DNS purposes. When, because of network problems, the server selects the secondary DNS setting, name resolution no longer occurs and connectivity is lost.


To resolve this issue, follow these steps:
  1. Right-click Network Neighborhood on the desktop, and then select Properties.
  2. Click the Protocols tab, select TCP/IP Protocol, and then click Properties.
  3. Click the DNS tab, and then in the DNS Service Search Order box, verify whether the IP addresses for the DNS servers listed are accurate. If an address is incorrect, click the Edit button to change the incorrect address to the correct address. If the address is valid but the server is no longer being used for DNS, click the Remove button to delete the entry.


To work around this issue, restart the server to force the DNS information to read into memory from the first DNS server in the list. This strategy is a temporary workaround until the next network failure.


For additional information about Event 9318, click the article number below
to view the article in the Microsoft Knowledge Base:

170056 XCON: Messages Back Up on MTA with Event 9215 and Event 9318

Artikelnummer: 261251 – Letzte Überarbeitung: 14.02.2017 – Revision: 1

Microsoft Exchange Server 4.0 Standard Edition, Microsoft Exchange Server 5.0 Standard Edition, Microsoft Exchange Server 5.5 Standard Edition