Orignally I thought this was a problem with JIRA plugin. My JIRA issues where being updated with the incorrect URL to Hudson builds after I updated the port that Hudson was running on. However, after a little digging it looking like the problem is hudson.model.Hudson.getInstance().getRootUrl(). This method seams to be getting the value from hudson.task.Mailer which in turn reads it from the file hudson.tasks.Mailer.xml. I'm not sure that the getRootUrl() method should be calling the Mailer to get this information? Either hudson.task.Mailer needs to be updated to keep the value up to date or the hudson.model.Hudson class need to get the value direct from the servlet context?