[squid-users] Reverse DNS Lookup for client IPs

[Amos Jeffries]

On 5/02/2016 12:41 a.m., Stefan Hölzle wrote:
> Hello,
> 
> I'm using a squid configured as proxy.
> According to the cache log, squid is doing a reverse dns lookup for
> client ips:
> 
> 78,3| dns_internal.cc(1794) idnsPTRLookup: idnsPTRLookup: buf is 42
> bytes for SOME_SOURCE_IP
> 
> I'm only using the following configuration parameters that might be
> relevant for this issue.
> external_acl_type
> acl aclname src
> acl aclname dst
> acl aclname dstdom_regex
> acl aclname port
> acl aclname proxy_auth
> acl aclname external
> acl aclname url_regex
> 
> Any ideas why squid is doing PTR lookups anyway ?

Because that list is incomplete.

The format parameters for external_acl_type, any *_extras rules for
helper formats, and logformat rules also may make use of the client
hostname (if any).

Also, anyone viewing the cachemanager clientdb report will trigger some
as the report is generated.

Amos