get first field from an nginx variable

[Daniele Melosi]

Hi All,

i've a variable on nginx with more fields, from phpinfo i can see its 
values are:

$HTTP_X_FORWARDED_FOR=192.168.1.3, 10.47.0.5, 94.47.0.6, 10.123.65.181

Is it possible to get only the first fields ?

Thanks in advance

Daniele