Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton mbroughton@advanis.net wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton mbroughton@advanis.net wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Is it a recent version of kamailio, or an older one?
Cheers, Daniel
On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng <loi.dangthanh@gmail.com mailto:loi.dangthanh@gmail.com> wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details. In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help. rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com <mailto:loi.dangthanh@gmail.com> On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton <mbroughton@advanis.net <mailto:mbroughton@advanis.net>> wrote: Hello, Long time Kam/Ser user, first time poster. I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end. They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network. I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet). My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's? Or, do I just need to poke them harder to fix their issues? My setup: Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider I hope I have provided enough information. Thanks! Michael _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
I'm using 5.3.1+stretch from deb.kamailio.org for our new setup. Our old setup was using 4.4.4+wheezy.
On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla miconda@gmail.com wrote:
Is it a recent version of kamailio, or an older one?
Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton mbroughton@advanis.net wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing Listsr-users@lists.kamailio.orghttps://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Just to provide some closure to this, the problem did end up being with the Via headers and our firewall ALG.
In the top Via header of the INVITE requests the ALG was transforming the internal proxy address to our external address and adding port 5060. In subsequent negative ACK and CANCEL requests, the ALG was transforming the internal proxy address to our external address with no port number. Thus the Via's did not exactly match, and this prevented our telco from matching the existing transaction.
I was able to fix the issue by modifying our Kam config with the advertise parameter:
listen = 10.x.y.z advertise 10.x.y.z:5060
With this setting in place the ALG is forced to behave itself.
On Thu, Jan 9, 2020 at 9:27 AM Michael Broughton mbroughton@advanis.net wrote:
I'm using 5.3.1+stretch from deb.kamailio.org for our new setup. Our old setup was using 4.4.4+wheezy.
On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla miconda@gmail.com wrote:
Is it a recent version of kamailio, or an older one?
Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton mbroughton@advanis.net wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing Listsr-users@lists.kamailio.orghttps://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Nice, be ware of the ALG, sometimes it's an unpredictable foe.
rgds, Loi Dang Thanh
On Tue, Jan 14, 2020 at 4:42 AM Michael Broughton mbroughton@advanis.net wrote:
Just to provide some closure to this, the problem did end up being with the Via headers and our firewall ALG.
In the top Via header of the INVITE requests the ALG was transforming the internal proxy address to our external address and adding port 5060. In subsequent negative ACK and CANCEL requests, the ALG was transforming the internal proxy address to our external address with no port number. Thus the Via's did not exactly match, and this prevented our telco from matching the existing transaction.
I was able to fix the issue by modifying our Kam config with the advertise parameter:
listen = 10.x.y.z advertise 10.x.y.z:5060
With this setting in place the ALG is forced to behave itself.
On Thu, Jan 9, 2020 at 9:27 AM Michael Broughton mbroughton@advanis.net wrote:
I'm using 5.3.1+stretch from deb.kamailio.org for our new setup. Our old setup was using 4.4.4+wheezy.
On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla < miconda@gmail.com> wrote:
Is it a recent version of kamailio, or an older one?
Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton < mbroughton@advanis.net> wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing Listsr-users@lists.kamailio.orghttps://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Curious about the ALG vendor/model/version, if it is some carrier/enterprise grade firewall, just to be aware when meeting it ... of course, if you can and want to share such details...
Cheers, Daniel
On 14.01.20 08:42, Lợi Đặng wrote:
Nice, be ware of the ALG, sometimes it's an unpredictable foe.
rgds, Loi Dang Thanh
On Tue, Jan 14, 2020 at 4:42 AM Michael Broughton <mbroughton@advanis.net mailto:mbroughton@advanis.net> wrote:
Just to provide some closure to this, the problem did end up being with the Via headers and our firewall ALG. In the top Via header of the INVITE requests the ALG was transforming the internal proxy address to our external address and adding port 5060. In subsequent negative ACK and CANCEL requests, the ALG was transforming the internal proxy address to our external address with no port number. Thus the Via's did not exactly match, and this prevented our telco from matching the existing transaction. I was able to fix the issue by modifying our Kam config with the advertise parameter: listen = 10.x.y.z advertise 10.x.y.z:5060 With this setting in place the ALG is forced to behave itself. On Thu, Jan 9, 2020 at 9:27 AM Michael Broughton <mbroughton@advanis.net <mailto:mbroughton@advanis.net>> wrote: I'm using 5.3.1+stretch from deb.kamailio.org <http://deb.kamailio.org> for our new setup. Our old setup was using 4.4.4+wheezy. On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla <miconda@gmail.com <mailto:miconda@gmail.com>> wrote: Is it a recent version of kamailio, or an older one? Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:Thank you, this was a helpful sanity check. We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly. The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers. Anyway, thanks again for your input. On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng <loi.dangthanh@gmail.com <mailto:loi.dangthanh@gmail.com>> wrote: Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details. In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help. rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com <mailto:loi.dangthanh@gmail.com> On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton <mbroughton@advanis.net <mailto:mbroughton@advanis.net>> wrote: Hello, Long time Kam/Ser user, first time poster. I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end. They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network. I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet). My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's? Or, do I just need to poke them harder to fix their issues? My setup: Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider I hope I have provided enough information. Thanks! Michael _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users-- Daniel-Constantin Mierla -- www.asipto.com <http://www.asipto.com> www.twitter.com/miconda <http://www.twitter.com/miconda> -- www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda> Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com <http://www.kamailioworld.com> _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
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FortiGate 200E, OS 6.0.6.
I opened a support ticket, but they didn't seem to worry about it once I found a workaround.
On Tue, Jan 14, 2020 at 2:21 AM Daniel-Constantin Mierla miconda@gmail.com wrote:
Curious about the ALG vendor/model/version, if it is some carrier/enterprise grade firewall, just to be aware when meeting it ... of course, if you can and want to share such details...
Cheers, Daniel On 14.01.20 08:42, Lợi Đặng wrote:
Nice, be ware of the ALG, sometimes it's an unpredictable foe.
rgds, Loi Dang Thanh
On Tue, Jan 14, 2020 at 4:42 AM Michael Broughton mbroughton@advanis.net wrote:
Just to provide some closure to this, the problem did end up being with the Via headers and our firewall ALG.
In the top Via header of the INVITE requests the ALG was transforming the internal proxy address to our external address and adding port 5060. In subsequent negative ACK and CANCEL requests, the ALG was transforming the internal proxy address to our external address with no port number. Thus the Via's did not exactly match, and this prevented our telco from matching the existing transaction.
I was able to fix the issue by modifying our Kam config with the advertise parameter:
listen = 10.x.y.z advertise 10.x.y.z:5060
With this setting in place the ALG is forced to behave itself.
On Thu, Jan 9, 2020 at 9:27 AM Michael Broughton mbroughton@advanis.net wrote:
I'm using 5.3.1+stretch from deb.kamailio.org for our new setup. Our old setup was using 4.4.4+wheezy.
On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla < miconda@gmail.com> wrote:
Is it a recent version of kamailio, or an older one?
Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton < mbroughton@advanis.net> wrote:
Hello,
Long time Kam/Ser user, first time poster.
I'm running into a problem with one of our telco providers when we make a call that ends up being not in service or some other error. In this case our ACK's are not working and the phone line stays open for a period of time until something times out on their end.
They claim the issue is that our negative ACK message is dropping one of the Via headers. This is the only case I can find in our setup where Kamailio does this. But it does drop the first Via, which is the first hop in our internal network.
I don't understand why this is a problem for them, and I'm still trying to get a reasonable explanation out of them. Technically, I don't see why it would be a problem. This behaviour is not an issue with our other telco providers. Strangely enough, it is also not an issue for this provider when we make the calls over their MPLS network (we are switching to the internet).
My question is, can this behaviour be changed in Kamailio somehow? Is there a way for it to keep all the Via headers for negative ACK's?
Or, do I just need to poke them harder to fix their issues?
My setup:
Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider
I hope I have provided enough information.
Thanks! Michael
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-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
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-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Best "workaround" is most likely disabling SIP ALG entirely. Fortinets along with Sonicwalls are notorious in this regard.
On Tue, Jan 14, 2020 at 10:54 AM Michael Broughton mbroughton@advanis.net wrote:
FortiGate 200E, OS 6.0.6.
I opened a support ticket, but they didn't seem to worry about it once I found a workaround.
On Tue, Jan 14, 2020 at 2:21 AM Daniel-Constantin Mierla < miconda@gmail.com> wrote:
Curious about the ALG vendor/model/version, if it is some carrier/enterprise grade firewall, just to be aware when meeting it ... of course, if you can and want to share such details...
Cheers, Daniel On 14.01.20 08:42, Lợi Đặng wrote:
Nice, be ware of the ALG, sometimes it's an unpredictable foe.
rgds, Loi Dang Thanh
On Tue, Jan 14, 2020 at 4:42 AM Michael Broughton mbroughton@advanis.net wrote:
Just to provide some closure to this, the problem did end up being with the Via headers and our firewall ALG.
In the top Via header of the INVITE requests the ALG was transforming the internal proxy address to our external address and adding port 5060. In subsequent negative ACK and CANCEL requests, the ALG was transforming the internal proxy address to our external address with no port number. Thus the Via's did not exactly match, and this prevented our telco from matching the existing transaction.
I was able to fix the issue by modifying our Kam config with the advertise parameter:
listen = 10.x.y.z advertise 10.x.y.z:5060
With this setting in place the ALG is forced to behave itself.
On Thu, Jan 9, 2020 at 9:27 AM Michael Broughton mbroughton@advanis.net wrote:
I'm using 5.3.1+stretch from deb.kamailio.org for our new setup. Our old setup was using 4.4.4+wheezy.
On Thu, Jan 9, 2020 at 9:16 AM Daniel-Constantin Mierla < miconda@gmail.com> wrote:
Is it a recent version of kamailio, or an older one?
Cheers, Daniel On 09.01.20 16:55, Michael Broughton wrote:
Thank you, this was a helpful sanity check.
We have been capturing SIP traces to try and debug this. I normally just look at the traffic on our Kam box because it is convenient to do so, but I have also taken traces on our firewall to check the ALG behaviour. The provider techs are also tracing these calls on their network as well. The ALG is new equipment in our setup, but as far as I can tell it is behaving correctly.
The one rather annoying discovery that I made is that when I call directly out from the source (Freeswitch in this case) and bypass Kamailio, the negative ACK's seem to work. I do not see any retransmissions of their final response. And of course the only significant difference in the SIP traces is the Via headers.
Anyway, thanks again for your input.
On Thu, Jan 9, 2020 at 4:04 AM Lợi Đặng loi.dangthanh@gmail.com wrote:
Hi, You're not going to have the Via header from your `source` sent to your `telco provider` in the negative ACK when the call is not answered, because the ACK in the right hand side of the call is created by the kamailio itself, not a forwarding one by the `source`. Yes, you've guessed it, ACK for an answered call is a forwarding one which contains all the Via headers. It's the SIP spec, not kamailio, you may want to dive into rfc3261 for more details.
In this case, your telco's expectation is not correct, my best guess is something went wrong with either your SIP ALG or Telco Provider. SIP capturing may help.
rgds, Loi Dang Thanh Phone : +84. 774.735.448 Email : loi.dangthanh@gmail.com
On Thu, Jan 9, 2020 at 2:42 AM Michael Broughton < mbroughton@advanis.net> wrote:
> Hello, > > Long time Kam/Ser user, first time poster. > > I'm running into a problem with one of our telco providers when we > make a call that ends up being not in service or some other error. In > this case our ACK's are not working and the phone line stays open for a > period of time until something times out on their end. > > They claim the issue is that our negative ACK message is dropping > one of the Via headers. This is the only case I can find in our setup where > Kamailio does this. But it does drop the first Via, which is the first hop > in our internal network. > > I don't understand why this is a problem for them, and I'm still > trying to get a reasonable explanation out of them. Technically, I don't > see why it would be a problem. This behaviour is not an issue with our > other telco providers. Strangely enough, it is also not an issue for this > provider when we make the calls over their MPLS network (we are switching > to the internet). > > My question is, can this behaviour be changed in Kamailio somehow? > Is there a way for it to keep all the Via headers for negative ACK's? > > Or, do I just need to poke them harder to fix their issues? > > My setup: > > Source -> Kamailio -> Firewall (NAT, SIP ALG) -> Telco Provider > > I hope I have provided enough information. > > Thanks! > Michael > > > _______________________________________________ > Kamailio (SER) - Users Mailing List > sr-users@lists.kamailio.org > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > _______________________________________________ Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing Listsr-users@lists.kamailio.orghttps://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing Listsr-users@lists.kamailio.orghttps://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Daniel-Constantin Mierla -- www.asipto.comwww.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - April 27-29, 2020, in Berlin -- www.kamailioworld.com
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
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Daniel-Constantin Mierla -
Lợi Đặng -
Michael Broughton -
Sergiu Pojoga