Hello,

b2evo recommends allow_url_fopen = Off. This is a good idea, but you use fopen() with an URL at the same time and thus you violate your own rules/recommendations (sounds harder than it should).
When sending Trackbacks with a HTTP GET request, b2evo uses fopen(). If allow_url_fopen is enabled, nothing is wrong, everything works. But if it's disabled, remote files can't be opened with PHP using fopen().

Because of this problem, I've rewritten the trackback() function in inc/comments/_trackback.funcs.php to use fsockopen() instead of fopen().

I don't know if this bug also exists in earlier b2evo versions, because I'm using only version 2.4.2 (additionally, I'm too lazy to download an old version and check the code :P).

Here is the diff then (to apply execute the command "patch -p1 < path/to/patch" on a shell in your b2evo root directory): http://files.ax86.net/b2evo/b2evo-2.4.2_trackback-fsockopen.patch

Nevertheless, b2evo is a great piece of software. Thanks!

Tblue