We have an Adtran 924e configured as an SBC. The outside provider is AT&T and inside is running 3CX PBX. All calls are working fine with one exception. When we have a call from the outside and we attempt to transfer it to another call on the outside we get a "500 Server Internal Error" from the SBC. Here are the relevant parts from the config.
voice feature-mode network
voice timeouts preconnected 0
voice timeouts preconnecting 0
voice transfer-mode local
voice forward-mode local
!
!
voice trunk T01 type sip
description "AT&T - Primary"
match dnis "NXX-XXXX" substitute "828-NXX-XXXX" name "Prepend Area Code"
sip-server primary 1.1.1.1
grammar from host local
!
voice trunk T02 type sip
description "AT&T - Secondary"
match dnis "NXX-XXXX" substitute "828-NXX-XXXX" name "Prepend Area Code"
sip-server primary 2.2.2.2
grammar from host local
!
voice trunk T04 type sip
description "3CX"
sip-server primary 10.16.0.6
grammar from host local
transfer-mode network
!
!
voice grouped-trunk AT&T
trunk T01
trunk T02
accept NXX-XXXX cost 0
accept 1-NXX-NXX-XXXX cost 0
accept NXX-NXX-XXXX cost 0
!
!
voice grouped-trunk 3CX
trunk T04
accept ***OUR INTERNAL NUMBERS ARE HERE*** cost 0
!
ip rtp symmetric-filter
ip rtp media-anchoring
And here are the SIP logs from the SBC:
15:42:05.380 SIP.MSG INVITE RSP RX 8281111111 8283333333
SIP/2.0 180 Ringing
From: "Test User"<sip:8281111111@3.3.3.3:5060;transport=UDP>;tag=5355bf0-20fd1daa-13c4-2bf59-9b6bffaa-2bf59
To: <sip:8283333333@1.1.1.1:5060>;tag=192453536-1492112525261
Call-ID: 53b2720-20fd1daa-13c4-2bf59-c555a872-2bf59@3.3.3.3
CSeq: 1 INVITE
Via: SIP/2.0/UDP 3.3.3.3:5060;branch=z9hG4bK-2bf59-abb76ec-335c53f7
Supported: timer
Call-Info: <sip:2.2.2.3>;appearance-index=1
Contact: <sip:1.1.1.1:5060;transport=udp>
Allow: INVITE,ACK,CANCEL,BYE,REFER,INFO,NOTIFY,PRACK,OPTIONS
Content-Disposition: session;handling=required
Content-Type: application/sdp
Content-Length: 217
v=0
o=BroadWorks 36898327 1 IN IP4 2.2.2.4
s=-
c=IN IP4 2.2.2.4
t=0 0
m=audio 31790 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=sendrecv
a=maxptime:20
15:42:05.384 SIP.MSG INVITE RSP TX 8281111111 8283333333
SIP/2.0 183 Session Progress
From: "Test User"<sip:8281111111@172.16.0.7:5060>;tag=ee4ac675
To: <sip:8283333333@172.16.0.7:5060>;tag=5328ad8-20fd1daa-13c4-2bf5b-b22b0b07-2bf5b
Call-ID: YzJhMWMxOTc4NGE0YjdkZmQ0MzI0MTQwOGI1YTE4MDY.
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.16.0.6:5060;rport=5060;branch=z9hG4bK-d8754z-ca08cc64a178df5f-1---d8754z-
Contact: <sip:8283333333@172.16.0.7:5060;transport=UDP>
Supported: 100rel,replaces
Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, PRACK, REFER, REGISTER
User-Agent: ADTRAN_Total_Access_924e_2nd_Gen/R12.3.1.E
Content-Type: application/sdp
Content-Length: 211
v=0
o=BroadWorks 36898327 1 IN IP4 172.16.0.7
s=-
c=IN IP4 172.16.0.7
t=0 0
m=audio 12444 RTP/AVP 0 101
a=sendrecv
a=maxptime:20
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
15:42:06.771 SIP.MSG INVITE REQ RX 8281111111 8283333333
INVITE sip:8283333333@172.16.0.7:5060 SIP/2.0
From: "9001"<sip:8281111111@172.16.0.7:5060>;tag=73205c30
To: <sip:8283333333@172.16.0.7:5060>
Call-ID: OGNhM2Q1ZTVkNTA5NGVlYzc0ZWEzNWQ3ZGY0NzRiM2Q.
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.16.0.6:5060;rport;branch=z9hG4bK-d8754z-a106c01783148111-1---d8754z-
Max-Forwards: 70
Supported: replaces
User-Agent: 3CXPhoneSystem 14.0.49169.513 (48654)
Remote-Party-ID: "8281111111"<sip:8281111111@172.16.0.7:5060>;party=calling
Contact: <sip:8281111111@10.16.0.6:5060>
Allow: INVITE,ACK,CANCEL,OPTIONS,BYE,REGISTER,SUBSCRIBE,NOTIFY,REFER,INFO,MESSAGE
Replaces: YzJhMWMxOTc4NGE0YjdkZmQ0MzI0MTQwOGI1YTE4MDY.;to-tag=5328ad8-20fd1daa-13c4-2bf5b-b22b0b07-2bf5b;from-tag=ee4ac675
Content-Length: 0
15:42:06.775 SIP.MSG INVITE RSP TX 8281111111 8283333333
SIP/2.0 100 Trying
From: "9001"<sip:8281111111@172.16.0.7:5060>;tag=73205c30
To: <sip:8283333333@172.16.0.7:5060>
Call-ID: OGNhM2Q1ZTVkNTA5NGVlYzc0ZWEzNWQ3ZGY0NzRiM2Q.
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.16.0.6:5060;rport=5060;branch=z9hG4bK-d8754z-a106c01783148111-1---d8754z-
Contact: <sip:8283333333@172.16.0.7:5060;transport=UDP>
Supported: 100rel,replaces
Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, PRACK, REFER, REGISTER
User-Agent: ADTRAN_Total_Access_924e_2nd_Gen/R12.3.1.E
Content-Length: 0
15:42:09.881 SIP.MSG INVITE RSP TX 8281111111 8283333333
SIP/2.0 500 Server Internal Error
From: "9001"<sip:8281111111@172.16.0.7:5060>;tag=73205c30
To: <sip:8283333333@172.16.0.7:5060>;tag=535f448-20fd1daa-13c4-2bf60-9f6daffd-2bf60
Call-ID: OGNhM2Q1ZTVkNTA5NGVlYzc0ZWEzNWQ3ZGY0NzRiM2Q.
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.16.0.6:5060;rport=5060;branch=z9hG4bK-d8754z-a106c01783148111-1---d8754z-
Supported: 100rel,replaces
Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, PRACK, REFER, REGISTER
User-Agent: ADTRAN_Total_Access_924e_2nd_Gen/R12.3.1.E
Content-Length: 0
