Avamar: Event Code 23017 (Reverse lookup failed to match page address provided by the client)

Summary: Event Code 23017 is received indicating that a reverse lookup failed. This is due to the Domain Name Server (DNS) responding with multiple IP addresses for a single hostname.

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Symptoms

The Avamar Management Console Server (MCS) generates warning events for Event Code 23017 (Reverse lookup failed to match page address provided by the client" or "Address from reverse lookup failed to match client address".)

Cause

The Domain Name Server (DNS) responds with multiple IP addresses for a single hostname.

Resolution

Identify the client causing the warning to generate.

1. Find the MCS log, or logs, that contain the event code:

grep 23017 /usr/local/avamar/var/mc/server_log/mcserver.log.*
 

2. Use view to open the mcserver log that logged the event code (for example mcserver.log.10)

view /usr/local/avamar/var/mc/server_log/mcserver.log.10
 
3. Search for the event code in the log.
  • Hint:
    • "Shift + G" to GO to the end of the log file. 
    • Reverse search for event code 23017 in view using "?23017"
 

Example log:

FINE: Already throttling: EventID=853161 PublishTime=1650441684820 EventCode=23017 <event-source NodeID="myavamarhost" ProgramName="Registration" ddr-id="" ddr-name="" 
gsan-version="19.4.0-116" hardware-id="APM00203702393" source-hardware-id="APM00203702393"/> EventData=<data><entry key="errNo" type="text" value="1" version="1"/>
<entry key="errText" type="text" value="Reverse lookup failed to match page address provided by the client" version="1"/><entry key="requestor" type="xml" 
value="&amp;lt;requestor domain=&amp;quot;/&amp;quot; product=&amp;quot;MCS&amp;quot; role=&amp;quot;Administrator&amp;quot; user=&amp;quot;root&amp;quot;/&amp;gt;" version=""/></data>
 
4. Once the event log is found, search or the last instance of validating a page address provided by a client before the event code was generated.
  • Hint:
    • Reverse search for the line using "?page address".
 

Example log:

FINE: validating page address:<Client_IP_Address> provided by client
 

5. Perform an nslookup of the IP address from the log using the DNS server.

nslookup <Client_IP_Address>

(This returns the hostname for the client.)

Example Output:

nslookup <Client_IP_Address>
<reverse_client_ip>.in-addr.arpa    name = <client_hostname>
 

6. Perform an nslookup of the hostname that was returned. It is likely that it has more than one IP Address:

nslookup <Client_IP_hostname>
Server: <customer_DNS_server>
Address: <customer_DNS_server>

Name: <client_hostname>
Address: <client_IP_1>
Name: <client_hostname>
Address: <client_IP_2>
Name: <client_hostname>
Address: <client_IP_3>
 

After confirming that the client hostname returns multiple IP addresses when querying the DNS, provide this information to the customer. The customer must work with their network teams to resolve the issue on their DNS server or servers.

Note: There may be more than one client with the issue.

Affected Products

Avamar
Article Properties
Article Number: 000198692
Article Type: Solution
Last Modified: 26 May 2026
Version:  6
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