SAP Basis Tech Supports

Symptom
- The SAProuter hangs temporarily in the DNS while establishing a connection;
Resolution of the IP address;
- A timeout terminates the connection after the Accept and before the system can continue to build the route.
Other terms
saprouter DNS reverse lookup
Reason and Prerequisites
The resolution of an IP address for the host name takes too much time and, therefore, slows down the SAProuter. This behavior can occur if the Domain Name Service (DNS) is set up incorrectly in connection with a high connection frequency on the SAProuter.
Solution
Optimize the settings of the Domain Name Service (DNS), for example, do not execute reverse lookups for top-level domains. Use the -D option of the SAProuter 36.7, which does not perform a reverse lookup for incoming connections. This is only a workaround, however, and does not correct the actual problem caused by an SAProuter slowed down by DNS resolutions.
The new -D option is supported as of SAProuter patch 6 or version 36.7, kernel Release 6.20.