I want to use existing components(Like News component, campaign components etc) for my newsletter mailings, and these components should point to the pages(respective detail pages) on which they have been linked as main components. Do I need to have custom link resolver for mailings?
If you track the Component Link (e.g. implicitly through the Post-processing TBB or explicitly by calling the GetLinkTrackingURL function), it will be resolved once people click on the link.
Basically, the link in the e-mail will point to the tracking URL you have configured on your Publication; said page will track the click action, call the Content Delivery Linking API to resolve the Component Link and redirect to the correct URL.
If there's a problem resolving the Component Link, it will instead redirect to the URL configured as the "ErrorResolvingLink" setting in cd_audience_manager_conf.xml.