On 09/05/2014 06:51 PM, Alex Villací­s Lasso wrote: I don't know that there are any functions to do that per se. But what you could do is extract the existing From header value, remove the From header, and append your own parameters to it: $var(new_from) = $hdr(From) + ";yourparam=yourval"; remove_hf("From"); append_hf("From: $var(new_from)\r\n"); Now, as to whether you actually want to be modifying From and To unilaterally, which of course breaks RFC 3261 and is definitely not something proxies should do, that's another matter. I would say don't do it. -- Alex Balashov - Principal Evariste Systems LLC Tel: +1-678-954-0670 Web: http://www.evaristesys.com/, http://www.alexbalashov.com/ Please be kind to the English language: http://www.entrepreneur.com/article/232906