[Spce-user] Missing ACK when dial from peering to SPCE

Andrew Pogrebennyk apogrebennyk at sipwise.com
Mon Sep 28 04:02:42 EDT 2015

it seems the same, but the reason is completely different now, there is
an additionally safety check in lb config which doesn't play well with
strict routing. I don't have such a device as they are quite rare by
now, but I believe you can workaround the issue yourself, just copy
cp /etc/ngcp-config/templates/etc/kamailio/lb/kamailio.cfg.tt2

edit the latter file and comment out the whole block which begins with
 if(uri_param("prxroute", "1")) around line 683.. Afterwards do
 ngcpcfg apply
P.S. probably, the check should check that $var(last_ip) equals to
sip_ext and not sip_int ips, in order to be compatible with strict
routing. But I have don't have the time right now to investigate and fix
it in upstream. However, I have this fix working in one customer.

Hope this helps,

Tung Tran wrote:
> Hi Andrew and All
> I changed strict_routing_safe: 'yes' and applied but it does't solve my
> problem, the lb still drops ACK package from Cisco gateway
> Here is the log from kamailio-lb.log 
> /Sep 25 19:25:54 spce lb[8628]: NOTICE: <script>: New request on lb -
> R=sip:x.x.x.x:6060;r2=on;lr=on;ftag=74E76334-5D1;nat=yes;ngcplb=yes;socket=udp:x.x.x.x:6060
> F=sip:2818573448 at y.y.y.y T=sip:17133751530 at x.x.x.x IP=udp:y.y.y.y:56266
> ID=C476CBE2-307B11D5-9770AB03-128F69C7 at y.y.y.y UA='<null>'/
> /Sep 25 19:25:54 spce lb[8628]: WARNING: <script>: Last hop of ACK
> points to 'x.x.x.x:6060' which is not a proxy, drop -
> R=sip:;prxroute=1
> ID=C476CBE2-307B11D5-9770AB03-128F69C7 at y.y.y.y UA='<null>'/
> There is not much thing I can do on Cisco's configuration to change its
> behaviors so there is anyway we can make the kaimailio-lb to accept that
> ACK and forward to proxy?
> Thank you all 

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