When Squid Cannot Resolve a Hostname

Inspect DNS where the failing lookup occurs. Your laptop resolving a name does not establish that Squid—or a parent making the onward connection—can resolve it.

Read the failing instance's cache log and server resolver settings. A supporting host-level check is:

getent ahosts target.example

Use the actual target. getent exercises the host's lookup arrangement; Squid's internal resolver or cache can differ. Inspect explicit dns_nameservers and hosts_file inputs before assuming they match.

For Squid 6.13, an explicit nameserver list contains IP addresses:

dns_nameservers 192.0.2.53

Replace this documentation address with an approved resolver reachable from the Squid server. Private names may require the organization's resolver; an unrelated public one can make them disappear from that DNS view.

A laptop hosts-file alias does not travel with a proxied hostname request. Review the hosts_file setting for the installed Squid version on the machine doing the lookup, and account for a parent resolver when applicable. Keep the hostname used for TLS identity consistent with the service.

After one controlled configuration change, parse and reload the intended instance, repeat the same request and inspect its evidence. Positive and negative cached answers can affect repeated tests. A successful lookup followed by a connection timeout is a later route or permission failure; do not keep changing DNS to fix it. Hold client DNS, parent routing and proxy protocol steady while evaluating the server change.