Update URLs in manual.

(cherry picked from commit f9dee9d6cc799707f1fdf17356f2d56b711d7c4d)
Update DNS section in manual.

(cherry picked from commit 8c3505a2ad188b88a085170fe9d3df18d9dd0f7d)
Update .gitignore.

(cherry picked from commit 0be1eb808695c8729fb0012044c40dd20f782f84)

Note: a minor conflict with upstream was corrected.