How to use tail -f with grep to show surrounding lines

grep has extra options to define how many lines before and after the result:

• -A (after)
• -B (before)
• -C (context [before + after])

So in your case you need -A:

YOUR_COMMAND |grep -A NUMBER YOURDOMAIN

the above command prints NUMBER of lines after YOURDOMAIN in file.

Try passing number of context lines to grep.

| grep -C 5

will print 5 lines before and after the match.