Trunk fails every day at same time?!?

[jmsflynn]

Hi,

 

I am currently using pbxnsip V3, and have been having a recuring problem. At 1429 every day all of my trunks decide to fail.

 

One of two errors occur. "408 Request Timeout" or "500 Address Resolution Failed".

 

Log below. I have included some of the log before and after the failure. For security i have also changed the IP, username and company names.

 

Any help or information would be really appriciated.

 

[8] 20100721142853: Trunk 3 (company2) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142853: Answer challenge with username 000000001

[8] 20100721142855: Trunk 3 (company2) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142855: Answer challenge with username 000000001

[8] 20100721142855: Trunk 6 (company3) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142855: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142855: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142855: Answer challenge with username 000000002

[8] 20100721142855: Answer challenge with username 000000003

[8] 20100721142855: Answer challenge with username 000000004

[8] 20100721142856: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142856: Answer challenge with username 000000005

[8] 20100721142856: Trunk 4 (company6) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142856: Answer challenge with username 000000006

[8] 20100721142905: DNS: dns_aaaa nat.voiptalk.org expired

[8] 20100721142905: Trunk 6 (company3) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142905: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142905: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142906: Answer challenge with username 000000003

[8] 20100721142906: Answer challenge with username 000000004

[8] 20100721142906: Answer challenge with username 000000002

[8] 20100721142906: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142906: Answer challenge with username 000000005

[8] 20100721142906: Trunk 4 (company6) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142906: Answer challenge with username 000000006

[8] 20100721142909: DNS: dns_a nat.voiptalk.org expired

[8] 20100721142925: Trunk 6 (company3) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142925: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142925: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142926: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142926: Trunk 4 (company6) has outbound proxy udp:77.255.49.201:5065

[8] 20100721142934: DNS: Add dns_a nat.voiptalk.org (ttl=60)

[7] 20100721142939: Other Ports: 5

[7] 20100721142939: Call Port: 378af7c3@pbx#1549215890

[7] 20100721142939: Call Port: 3c44897f63ccb4a87c06a9c04b4df10d@217.14.138.126#355ed59ad8

[7] 20100721142939: Call Port: 64e367f05e467324095341a007d6b672@77.240.60.33#cf4b451a80

[7] 20100721142939: Call Port: MTM0MzQyNzJhYWY4ZjIyODljNzRiMjg4MzliZTk2NzY.#538e78e549

[7] 20100721142939: Call Port: d72de713@pbx#1679405994

[7] 20100721142939: Call 64e367f05e467324095341a007d6b672@77.240.60.33#cf4b451a80: Clear last request

[5] 20100721142939: BYE Response: Terminate 64e367f05e467324095341a007d6b672@77.240.60.33

[7] 20100721142939: Other Ports: 4

[7] 20100721142939: Call Port: 378af7c3@pbx#1549215890

[7] 20100721142939: Call Port: 3c44897f63ccb4a87c06a9c04b4df10d@217.14.138.126#355ed59ad8

[7] 20100721142939: Call Port: MTM0MzQyNzJhYWY4ZjIyODljNzRiMjg4MzliZTk2NzY.#538e78e549

[7] 20100721142939: Call Port: d72de713@pbx#1679405994

[5] 20100721142953: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[2] 20100721142953: Trunk status company2 (3) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[8] 20100721142954: DNS: Add dns_aaaa nat.voiptalk.org (ttl=60)

[6] 20100721142954: Could not determine destination address on 1068564

[5] 20100721142954: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068531

[2] 20100721142954: Trunk status company2 (3) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[5] 20100721142954: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068534

[5] 20100721142954: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068535

[5] 20100721142954: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[2] 20100721142954: Trunk status company3 (6) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142954: Could not determine destination address on 1068536

[5] 20100721142954: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[2] 20100721142954: Trunk status company4 (5) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142954: Could not determine destination address on 1068565

[2] 20100721142954: Trunk status company1 (7) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[5] 20100721142954: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068566

[5] 20100721142954: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068567

[5] 20100721142954: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068540

[5] 20100721142954: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[2] 20100721142954: Trunk status company5 (2) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142954: Could not determine destination address on 1068568

[5] 20100721142954: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068542

[5] 20100721142954: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[2] 20100721142954: Trunk status company6 (4) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142954: Could not determine destination address on 1068569

[5] 20100721142954: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[6] 20100721142954: Could not determine destination address on 1068560

[5] 20100721142954: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[5] 20100721142955: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[2] 20100721142955: Trunk status company3 (6) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[5] 20100721142955: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[2] 20100721142955: Trunk status company4 (5) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[5] 20100721142955: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[2] 20100721142955: Trunk status company1 (7) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[6] 20100721142956: Could not determine destination address on 1068571

[5] 20100721142956: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company4 (5) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142956: Could not determine destination address on 1068572

[5] 20100721142956: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company1 (7) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[6] 20100721142956: Could not determine destination address on 1068573

[5] 20100721142956: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company3 (6) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[5] 20100721142956: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company5 (2) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[6] 20100721142956: Could not determine destination address on 1068574

[5] 20100721142956: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company5 (2) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[5] 20100721142956: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company6 (4) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[6] 20100721142956: Could not determine destination address on 1068576

[5] 20100721142956: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[2] 20100721142956: Trunk status company6 (4) changed to "500 Address Resolution Failed" (Registration failed, retry after 60 seconds)

[7] 20100721143000: Other Ports: 3

[7] 20100721143000: Call Port: 378af7c3@pbx#1549215890

[7] 20100721143000: Call Port: 3c44897f63ccb4a87c06a9c04b4df10d@217.14.138.126#355ed59ad8

[7] 20100721143000: Call Port: MTM0MzQyNzJhYWY4ZjIyODljNzRiMjg4MzliZTk2NzY.#538e78e549

[7] 20100721143000: Call 3c44897f63ccb4a87c06a9c04b4df10d@217.14.138.126#355ed59ad8: Clear last request

[5] 20100721143000: BYE Response: Terminate 3c44897f63ccb4a87c06a9c04b4df10d@217.14.138.126

[7] 20100721143000: Other Ports: 2

[7] 20100721143000: Call Port: 378af7c3@pbx#1549215890

[7] 20100721143000: Call Port: MTM0MzQyNzJhYWY4ZjIyODljNzRiMjg4MzliZTk2NzY.#538e78e549

[5] 20100721143015: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[2] 20100721143015: Trunk status company2 (3) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[7] 20100721143016: Other Ports: 1

[7] 20100721143016: Call Port: 378af7c3@pbx#1549215890

[7] 20100721143016: Call 378af7c3@pbx#1549215890: Clear last request

[5] 20100721143016: BYE Response: Terminate 378af7c3@pbx

[5] 20100721143024: Registration on trunk 3 (company2) failed. Retry in 60 seconds

[5] 20100721143024: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[2] 20100721143024: Trunk status company4 (5) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[5] 20100721143024: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[5] 20100721143024: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[2] 20100721143024: Trunk status company1 (7) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[2] 20100721143024: Trunk status company3 (6) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[5] 20100721143024: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[5] 20100721143024: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[2] 20100721143024: Trunk status company5 (2) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[2] 20100721143024: Trunk status company6 (4) changed to "408 Request Timeout" (Registration failed, retry after 60 seconds)

[5] 20100721143025: Identify trunk (domain name match) 7

[8] 20100721143025: Tagging request with existing tag

[6] 20100721143025: Sending RTP for MzQyMDIyYjg5YzBkYmY5NjViNmM3Y2MwNDhiYWY0ZTk.#a7251d22e5 to 192.168.1.16:38426

[5] 20100721143025: Dialplan company5: Match 07939523884@khpbxserver to <sip:07939523884@voiptalk.org;user=phone> on trunk company5

[8] 20100721143025: Play audio_moh/noise.wav

[6] 20100721143025: Could not determine destination address on 1068603

[7] 20100721143025: Call d2ac0e53@pbx#1805635349: Clear last INVITE

[5] 20100721143025: INVITE Response 500 Address Resolution Failed: Terminate d2ac0e53@pbx

[7] 20100721143025: Other Ports: 1

[7] 20100721143025: Call Port: MzQyMDIyYjg5YzBkYmY5NjViNmM3Y2MwNDhiYWY0ZTk.#a7251d22e5

[6] 20100721143025: Send codec pcmu/8000

[5] 20100721143026: Registration on trunk 5 (company4) failed. Retry in 60 seconds

[5] 20100721143026: Registration on trunk 7 (company1) failed. Retry in 60 seconds

[5] 20100721143026: Registration on trunk 6 (company3) failed. Retry in 60 seconds

[5] 20100721143026: Registration on trunk 2 (company5) failed. Retry in 60 seconds

[5] 20100721143026: Registration on trunk 4 (company6) failed. Retry in 60 seconds

[5] 20100721143031: SIP port accept from 192.168.1.16:51135

[5] 20100721143031: Identify trunk (domain name match) 7

[8] 20100721143031: Tagging request with existing tag

[6] 20100721143031: Sending RTP for ODc0NDQ5YjVmMDMzOGExYjgxNmRlZmQwOTBmMDY1NTM.#45e5188bed to 192.168.1.16:26122

[5] 20100721143031: Dialplan company5: Match 07939523884@khpbxserver to <sip:07939523884@voiptalk.org;user=phone> on trunk company5

[8] 20100721143031: Play audio_moh/noise.wav

[6] 20100721143031: Could not determine destination address on 1068612

[7] 20100721143031: Call 52c96a7a@pbx#759885658: Clear last INVITE

[5] 20100721143031: INVITE Response 500 Address Resolution Failed: Terminate 52c96a7a@pbx

[7] 20100721143031: Other Ports: 1

[7] 20100721143031: Call Port: ODc0NDQ5YjVmMDMzOGExYjgxNmRlZmQwOTBmMDY1NTM.#45e5188bed

[6] 20100721143031: Send codec pcmu/8000

[5] 20100721143033: Identify trunk (domain name match) 7

[8] 20100721143033: Tagging request with existing tag

[6] 20100721143033: Sending RTP for NmMwMTJiOGM1NWIwNzNmMTZkYmE5MTRhY2U5YTgwMTI.#6172f6bf6a to 192.168.1.78:63498

[5] 20100721143033: Dialplan company5: Match 01422358164@khpbxserver to <sip:01422358164@voiptalk.org;user=phone> on trunk company5

[8] 20100721143033: Play audio_moh/noise.wav

[6] 20100721143033: Could not determine destination address on 1068619

[7] 20100721143033: Call 8efa6aac@pbx#1708055905: Clear last INVITE

[5] 20100721143033: INVITE Response 500 Address Resolution Failed: Terminate 8efa6aac@pbx

[7] 20100721143033: Other Ports: 1

[7] 20100721143033: Call Port: NmMwMTJiOGM1NWIwNzNmMTZkYmE5MTRhY2U5YTgwMTI.#6172f6bf6a

[6] 20100721143033: Send codec pcmu/8000

[8] 20100721143034: DNS: dns_a nat.voiptalk.org expired

[3] 20100721143036: Source address for "408"<sip:408@khpbxserver>;tag=e823e124 has changed from udp:192.168.1.16:26818 to tcp:192.168.1.16:51135

[5] 20100721143041: Identify trunk (domain name match) 7

[8] 20100721143041: Tagging request with existing tag

[6] 20100721143041: Sending RTP for ODRkMGZjNWYyMWM3Y2I2MWVhMzVjMTFlMTkyMmJmNWU.#4762c9dd91 to 192.168.1.68:60654

[5] 20100721143041: Dialplan company5: Match 07970541302@khpbxserver to <sip:07970541302@voiptalk.org;user=phone> on trunk company5

[8] 20100721143041: Play audio_moh/noise.wav

[6] 20100721143041: Send codec pcmu/8000

[5] 20100721143041: SIP port accept from 192.168.1.78:51844

[3] 20100721143041: Source address for "409"<sip:409@khpbxserver>;tag=406ce92e has changed from udp:192.168.1.78:53212 to tcp:192.168.1.78:51844

[8] 20100721143049: DNS: Add dns_a nat.voiptalk.org 77.255.49.201 (ttl=86297)

[8] 20100721143049: Answer challenge with username 000000005

[7] 20100721143049: Call 7ca301a5@pbx#354549183: Clear last INVITE

[5] 20100721143049: INVITE Response 500 Server internal error: Terminate 7ca301a5@pbx

[7] 20100721143049: Other Ports: 1

[7] 20100721143049: Call Port: ODRkMGZjNWYyMWM3Y2I2MWVhMzVjMTFlMTkyMmJmNWU.#4762c9dd91

[8] 20100721143054: DNS: dns_aaaa nat.voiptalk.org expired

[5] 20100721143055: SIP port accept from 192.168.1.68:52394

[3] 20100721143055: Source address for "401"<sip:401@khpbxserver>;tag=d3523173 has changed from udp:192.168.1.68:38796 to tcp:192.168.1.68:52394

[5] 20100721143101: Identify trunk (domain name match) 7

[8] 20100721143101: Tagging request with existing tag

[6] 20100721143101: Sending RTP for MWQxYmE0MmYyMjYwYzBjMjQxM2JiYWZmMDhkNTQzOGU.#2bd49778d2 to 192.168.1.68:23670

[5] 20100721143101: Dialplan company5: Match 07970541302@khpbxserver to <sip:07970541302@voiptalk.org;user=phone> on trunk company5

[8] 20100721143101: Play audio_moh/noise.wav

[6] 20100721143101: Send codec pcmu/8000

[8] 20100721143101: Answer challenge with username 000000005

[7] 20100721143102: Call becd776f@pbx#1113048562: Clear last INVITE

[5] 20100721143102: INVITE Response 500 Server internal error: Terminate becd776f@pbx

[7] 20100721143102: Other Ports: 1

[7] 20100721143102: Call Port: MWQxYmE0MmYyMjYwYzBjMjQxM2JiYWZmMDhkNTQzOGU.#2bd49778d2

[2] 20100721143135: Web interface triggered reregistration of trunk 2

[5] 20100721143137: Identify trunk (domain name match) 7

[8] 20100721143137: Tagging request with existing tag

[6] 20100721143137: Sending RTP for OWM3ZGMyMjMyMjEwNjViODNjNjE2MTVhZDk5OWFmMjI.#5af4a52570 to 192.168.1.71:14544

[5] 20100721143137: Dialplan company5: Match 01342321303@khpbxserver to <sip:01342321303@voiptalk.org;user=phone> on trunk company5

[8] 20100721143137: Play audio_moh/noise.wav

[6] 20100721143137: Send codec pcmu/8000

[8] 20100721143137: Answer challenge with username 000000005

[2] 20100721143138: Web interface triggered reregistration of trunk 2

[2] 20100721143141: Last message repeated 2 times

[2] 20100721143141: Web interface triggered reregistration of trunk 7

[7] 20100721143142: Set packet length to 20

[6] 20100721143142: Send codec=pcma/8000 afrer answer

[6] 20100721143142: Sending RTP for d4d0b998@pbx#1695546007 to 77.240.48.210:59278

[7] 20100721143142: d4d0b998@pbx#1695546007: RTP pass-through mode

[7] 20100721143142: OWM3ZGMyMjMyMjEwNjViODNjNjE2MTVhZDk5OWFmMjI.#5af4a52570: RTP pass-through mode

[7] 20100721143142: Cannot pass through on OWM3ZGMyMjMyMjEwNjViODNjNjE2MTVhZDk5OWFmMjI.#5af4a52570, falling back to transcoding

[7] 20100721143142: Cannot pass through on d4d0b998@pbx#1695546007, falling back to transcoding

[2] 20100721143143: Web interface triggered reregistration of trunk 4

[8] 20100721143143: DNS: Add dns_aaaa nat.voiptalk.org (ttl=60)

[8] 20100721143143: Trunk 3 (company2) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 6 (company3) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 4 (company6) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Last message repeated 3 times

[8] 20100721143143: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143143: Trunk 4 (company6) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143144: Answer challenge with username 000000001

[8] 20100721143144: Answer challenge with username 000000003

[8] 20100721143144: Answer challenge with username 000000004

[8] 20100721143144: Answer challenge with username 000000002

[8] 20100721143144: Answer challenge with username 000000005

[8] 20100721143144: Answer challenge with username 000000006

[8] 20100721143144: Answer challenge with username 000000005

[8] 20100721143144: Last message repeated 3 times

[8] 20100721143144: Answer challenge with username 000000004

[8] 20100721143144: Answer challenge with username 000000006

[2] 20100721143144: Trunk status company2 (3) changed to "200 OK" (Refresh interval 20 seconds)

[2] 20100721143144: Trunk status company4 (5) changed to "200 OK" (Refresh interval 20 seconds)

[2] 20100721143144: Trunk status company1 (7) changed to "200 OK" (Refresh interval 20 seconds)

[2] 20100721143144: Trunk status company3 (6) changed to "200 OK" (Refresh interval 20 seconds)

[2] 20100721143144: Web interface triggered reregistration of trunk 5

[8] 20100721143144: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[2] 20100721143144: Trunk status company5 (2) changed to "200 OK" (Refresh interval 20 seconds)

[2] 20100721143144: Trunk status company6 (4) changed to "200 OK" (Refresh interval 20 seconds)

[8] 20100721143144: Answer challenge with username 000000003

[2] 20100721143146: Web interface triggered reregistration of trunk 2

[8] 20100721143146: Trunk 2 (company5) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143146: Answer challenge with username 000000005

[8] 20100721143154: Trunk 3 (company2) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143154: Answer challenge with username 000000001

[8] 20100721143156: Trunk 5 (company4) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143156: Trunk 7 (company1) has outbound proxy udp:77.255.49.201:5065

[8] 20100721143156: Trunk 6 (company3) has outbound proxy udp:77.255.49.201:5065

[7] 20100721143156: Call d4d0b998@pbx#1695546007: Clear last INVITE

[7] 20100721143156: Set packet length to 20

[7] 20100721143156: Determine pass-through mode after receiving response

[Vodia PBX]

Is there anything in the DNS that expires after one day? Maybe a problem with DNS then. If you can, try to change the DNS TTL to another value and check if that changes the frequency of the problem.

 

DNS seems like a very well established protocol, but there are still cases where the router refused to relay certain messages and UDP fragmentation (DNS is using UDP after all) is causing issues.

[jmsflynn]

Thanks for the help, I questioned our ISP as it is a managed router, they told me they have looked at both the primary and secoundry DNS server and neither of them are caching anything apparently.

 

I then spoke to my Voip provider voiptalk, who advised me to edit my host file to point to a specific IP address when the pbx tries to register to the voiptalk domain. This seems to have cleared things up.

 

Thanks for you help.