Benoit Panizzon
2023-Feb-27 13:43 UTC
[asterisk-users] Asterisk PJSIP setting don't fragment bit on UDP
Hi Gang I noticed, that when I enable multiple codecs and rtp encrypting (generating a large SDP) invites with credentials do not get through anymore. So sniffed the connection and found that the IP packets have the don't fragment bit set, causing a VDSL router with 1472 MTU in the path to reject them. So it asterisk or the underlying OS the culpit? nping --udp -g 5070 -p 5060 registrarIP --data-length 1472 sniffing both sides. nping issues packets without don't fragment bit. Router fragments them, registrar receives two fragmented packets per one sent packet. So I guess it's asterisk which forcefully is setting don't fragment. But I could not find any such setting regarding SIP. Did I miss something? How do I make asterisk not set the don't fragment bit on UDP? Mit freundlichen Grüssen -Benoît Panizzon- -- I m p r o W a r e A G - Leiter Commerce Kunden ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 00 CH-4133 Pratteln Fax +41 61 826 93 01 Schweiz Web http://www.imp.ch ______________________________________________________