Hi Henning, I have tried modparam("ims_registrar_scscf", "max_contacts", 1), but it does not seem to do anything. When doing multiple registration & re-registration, it still shows multiple contacts. I am using v 5.2.3, would this be a bug? Thanks, --Charles -----Original Message----- From: Henning Westerholt &lt;hw(a)skalatan.de&gt; Sent: Sunday, December 08, 2019 4:17 PM To: Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt; Cc: Liu, Charles (US) &lt;Charles.Liu(a)L3Harris.com&gt; Subject: RE: duplicated registrations Hello Liu, You could e.g. use this parameter to restrict multiple registrations: https://kamailio.org/docs/modules/5.3.x/modules/registrar.html#registrar.p.… Cheers, Henning -- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.com -----Original Message----- From: sr-users &lt;sr-users-bounces(a)lists.kamailio.org&gt; On Behalf Of Liu, Charles Sent: Sunday, December 8, 2019 11:52 AM To: sr-users(a)lists.kamailio.org Subject: [SR-Users] duplicated registrations Hi All, Does this look correct? I am using Zoiper client and did multiple registration/re-registration, but I saw duplicated contacts in the database for the same user/device(alice). I was expecting to see only one. Is this a bug? How do I prevent this happening? "select * from scscf.contact" id contact params path received user_agent expires callid 49 sip:bob@192.168.10.201:60944;rinstance=44b4024df17bd284;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:31:51 r7jCYp7JuVbA8QjocnouLw.. 64 sip:alice@192.168.10.241:60383;rinstance=e850d3ed0605bcd3;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:31:11 EHLOADkLUEe8d0CMpdLL9A.. 142 sip:alice@192.168.10.241:60383;rinstance=bc755d87cc438890;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:31:51 P1rBkHGUVdv7oqW3_UWQPg.. 143 sip:alice@192.168.10.241:60383;rinstance=146303cf7501a125;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:32:15 etUEoAGSM4q4e_39wFKa7w.. 144 sip:alice@192.168.10.241:60383;rinstance=e0a260b7b78ecf6b;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:32:17 WUtIYeGlBZmHD3TGklmKCQ.. 145 sip:alice@192.168.10.241:60383;rinstance=2681245431c4e4e4;transport=UDP NULL <sip:term@pcscf.mnc001.mnc001.3gppnetwork.org;lr> Zoiper rv2.10.3.2 2019-12-08 10:32:19 HNZPyeO173jfscKYNOT0bw.. Thanks, --Charles CONFIDENTIALITY NOTICE: This email and any attachments are for the sole use of the intended recipient and may contain material that is proprietary, confidential, privileged or otherwise legally protected or restricted under applicable government laws. Any review, disclosure, distributing or other use without expressed permission of the sender is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies without reading, printing, or saving. _______________________________________________ Kamailio (SER) - Users Mailing List sr-users(a)lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users