1. A method for reducing network traffic used for DNS queries in a wireless network, the method, comprising: querying cached DNS entries in a local cache on a mobile device for a host name associated with an outgoing DNS query from the mobile device, wherein each cached DNS entry stores an association between a domain name and a network address; and providing a matching cached DNS entry as a response to the outgoing DNS query without accessing the wireless network; wherein the matching cached DNS entry is invalidated in the local cache when a proxy remote from the mobile device detects a response for the outgoing DNS query and notifies the mobile device to invalidate the matching locally cached DNS entry; and wherein the matching cached DNS entry is also invalidated in the local cache when a proxy remote from the mobile device originates a DNS query, detects a changed DNS response to the proxy-originated DNS query, and, in response to detecting the changed DNS response for the proxy-originated DNS query, notifies the mobile device to invalidate the matching locally cached DNS entry, wherein the proxy-originated DNS query is performed in response to sending, by the mobile device, a polling task to the proxy that instructs the proxy to poll a name server to monitor for changes in responses to the proxy-originated DNS query, wherein the polling task includes timing data such that the proxy-originated DNS query occurs before the mobile device performs a corresponding query to its local cache, wherein the timing data is determined based on the freshness of mobile content.