/viewforum.php?f=1 becomes /forum/1//viewtopic.php?f=1&t=2 becomes /forum/1/topic/2//viewtopic.php?f=1&t=2&start=3 becomes /forum/1/topic/2/start/3//viewtopic.php?p=1 becomes /post/1/
nginx config rules. add these to location / {
rewrite ^/forum/([0-9])/mcp.php(.) mcp.php?$query_string last;
rewrite ^/forum/([0-9])/topic/([0-9])/start/([0-9]*) /viewtopic.php?f=$1&t=$2&start=$3&$query_string last;
rewrite ^/forum/([0-9])/topic/([0-9])/start/([0-9]*)/ /viewtopic.php?f=$1&t=$2&start=$3&$query_string last;
rewrite ^/forum/([0-9])/topic/([0-9])/ /viewtopic.php?f=$1&t=$2&$query_string last;
rewrite ^/forum/([0-9])/topic/([0-9]) /viewtopic.php?f=$1&t=$2&$query_string last;
rewrite ^/forum/([0-9])/start/([0-9]) /viewforum.php?f=$1&start=$2&$query_string last;
rewrite ^/forum/([0-9]*)/ /viewforum.php?f=$1&$query_string last;
rewrite ^/forum/([0-9]*) /viewforum.php?f=$1&$query_string last;
rewrite ^/post/([0-9]*)/$ /viewtopic.php?p=$1&$query_string last;