Configure SWG to Vary Source Port for DNS Queries
In SWG, DNS queries use the same source port for up to 1000 queries. You can configure the number of queries performed before another source port is used.
To vary the source port for DNS queries in SWG, perform the following steps:
- Log on to the SWG user interface.
- Select Configuration > File Editor.
- Select the SWG configuration file.
- Locate and modify the following section. Remove the comment-out (#) and change the value of DNS_PORT_REUSAGE_LIMIT from 0 to any value:
NOTE: If the section doesn't exist, add it to the file manually.
From:
#renew the port for dns lookups. Set to 0 to disable (default: 1000)
#DNS_PORT_REUSAGE_LIMIT=0
#export DNS_PORT_REUSAGE_LIMIT
To:
# renew the port for dns lookups. Set to 0 to disable (default: 1000)
DNS_PORT_REUSAGE_LIMIT=1
export DNS_PORT_REUSAGE_LIMIT
NOTE: In this example, because the setting is 1, a different source port is used for each query. Set this value to any number between 1 and 1000.
- Click Save.
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