Hi,
I would like to know the reason for having "off" as default value for use_dns_failover. https://github.com/kamailio/kamailio/issues/3547
Greetings, Silvan
Hello,
DNS-based routing is not very common in telecommunications, most of the interconnects being done based on IP routing and IP-trusted rules. Because DNS is usually a blocking operation that involves network communication (therefore can introduce delays), many of the dns features are turned off by default. When one has to build a system that relies significantly on DNS-based routing, those features can be turned on via config.
Cheers, Daniel
On 22.08.23 17:07, Silvan Nagl wrote:
Hi,
I would like to know the reason for having "off" as default value for use_dns_failover. https://github.com/kamailio/kamailio/issues/3547
Greetings, Silvan
I agree with Daniel here. Within the platforms we rarely use DNS as most systems are fixed (not moving around, have a permanent IP address) and we handle failover and load balancing using solutions like the Kamailio dispatcher.
From the client side, like softphones or desktop phones, I personally use a lot of DNS to find the first hop SIP server. This way I can manage the clients, control load balancing, provider failover and make sure they always reach the service.
Cheers, /O
On 22 Aug 2023, at 21:14, Daniel-Constantin Mierla miconda@gmail.com wrote:
Hello,
DNS-based routing is not very common in telecommunications, most of the interconnects being done based on IP routing and IP-trusted rules. Because DNS is usually a blocking operation that involves network communication (therefore can introduce delays), many of the dns features are turned off by default. When one has to build a system that relies significantly on DNS-based routing, those features can be turned on via config.
Cheers, Daniel
On 22.08.23 17:07, Silvan Nagl wrote:
Hi,
I would like to know the reason for having "off" as default value for use_dns_failover. https://github.com/kamailio/kamailio/issues/3547
Greetings, Silvan
-- Daniel-Constantin Mierla -- www.asipto.com www.twitter.com/miconda -- www.linkedin.com/in/miconda Kamailio World Conference - www.kamailioworld.com
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I'd argue that even *IF* name resolution became increasingly common, that changing defaults would tend to break existing configs and is not something that should be done lightly. In this case, general practice is to handle the failure in the script logic on branch failure, and so the feature is disabled. If it was decided that the default were to be changed in 5.8, how many deployments would break as a result of this?
If this was a greenfield new piece of software, I think that having DNS failover enabled by default might not be a bad decision. But this isn't net-new software. It's something that has existing expectations.
-----Original Message----- From: Olle E. Johansson oej@edvina.net Sent: Wednesday, August 23, 2023 1:54 AM To: Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org Cc: Silvan Nagl silvan.nagl@ucware.com Subject: [SR-Users] Re: use_dns_failover default value
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I agree with Daniel here. Within the platforms we rarely use DNS as most systems are fixed (not moving around, have a permanent IP address) and we handle failover and load balancing using solutions like the Kamailio dispatcher.
From the client side, like softphones or desktop phones, I personally use a lot of DNS to find the first hop SIP server. This way I can manage the clients, control load balancing, provider failover and make sure they always reach the service.
Cheers, /O
On 22 Aug 2023, at 21:14, Daniel-Constantin Mierla miconda@gmail.com wrote:
Hello,
DNS-based routing is not very common in telecommunications, most of the interconnects being done based on IP routing and IP-trusted rules. Because DNS is usually a blocking operation that involves network communication (therefore can introduce delays), many of the dns features are turned off by default. When one has to build a system that relies significantly on DNS-based routing, those features can be turned on via config.
Cheers, Daniel
On 22.08.23 17:07, Silvan Nagl wrote:
Hi,
I would like to know the reason for having "off" as default value for use_dns_failover. https://git/ hub.com%2Fkamailio%2Fkamailio%2Fissues%2F3547&data=05%7C01%7Cbkaufman %40bcmone.com%7C5cd1830270534a45fd9708dba3a7652d%7Cafc1818e7b68485689 13201b9396c4fc%7C1%7C0%7C638283711594119946%7CUnknown%7CTWFpbGZsb3d8e yJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3 000%7C%7C%7C&sdata=4GaP2jVvIMMFXi1f5nWMRt3KF6F723rPZUbNuDzyU%2Bw%3D&r eserved=0
Greetings, Silvan
-- Daniel-Constantin Mierla -- http://www.a/ sipto.com%2F&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1830270534a45fd 9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C6382837115 94119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=8fi7fgZqNKMbb67Vm7 X0TlI1B5BGk8QzS5kiiE3WvPw%3D&reserved=0 http://www.t/ witter.com%2Fmiconda&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1830270 534a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C63 8283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV 2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=5g6rGiCfkG Yrd7l5XnJdjqNbzL27pnax3WdoSksHThU%3D&reserved=0 -- http://www.l/ inkedin.com%2Fin%2Fmiconda&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1 830270534a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C 0%7C638283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=8tVs EpkONunTFeq1KJdn4FPCXWUhm2vEpIsOmAuEMSU%3D&reserved=0 Kamailio World Conference - http://www.k/ amailioworld.com%2F&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd18302705 34a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C638 283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2 luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=PjA3NmvxI9E 7l88a7nux21mHdnRs0ajPDxUTShKrvds%3D&reserved=0
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Agree with what has been said here. DNS is far too unwieldy and unpredictable to leave enabled by default. If you want the wild west of DNS, you should have to consciously opt in.
— Sent from mobile, apologies for brevity and errors.
On Aug 23, 2023, at 10:10 AM, Ben Kaufman bkaufman@bcmone.com wrote:
I'd argue that even *IF* name resolution became increasingly common, that changing defaults would tend to break existing configs and is not something that should be done lightly. In this case, general practice is to handle the failure in the script logic on branch failure, and so the feature is disabled. If it was decided that the default were to be changed in 5.8, how many deployments would break as a result of this?
If this was a greenfield new piece of software, I think that having DNS failover enabled by default might not be a bad decision. But this isn't net-new software. It's something that has existing expectations.
-----Original Message----- From: Olle E. Johansson oej@edvina.net Sent: Wednesday, August 23, 2023 1:54 AM To: Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org Cc: Silvan Nagl silvan.nagl@ucware.com Subject: [SR-Users] Re: use_dns_failover default value
CAUTION: This email originated from outside the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
I agree with Daniel here. Within the platforms we rarely use DNS as most systems are fixed (not moving around, have a permanent IP address) and we handle failover and load balancing using solutions like the Kamailio dispatcher.
From the client side, like softphones or desktop phones, I personally use a lot of DNS to find the first hop SIP server. This way I can manage the clients, control load balancing, provider failover and make sure they always reach the service.
Cheers, /O
On 22 Aug 2023, at 21:14, Daniel-Constantin Mierla miconda@gmail.com wrote:
Hello,
DNS-based routing is not very common in telecommunications, most of the interconnects being done based on IP routing and IP-trusted rules. Because DNS is usually a blocking operation that involves network communication (therefore can introduce delays), many of the dns features are turned off by default. When one has to build a system that relies significantly on DNS-based routing, those features can be turned on via config.
Cheers, Daniel
On 22.08.23 17:07, Silvan Nagl wrote: Hi,
I would like to know the reason for having "off" as default value for use_dns_failover. https://git/ hub.com%2Fkamailio%2Fkamailio%2Fissues%2F3547&data=05%7C01%7Cbkaufman %40bcmone.com%7C5cd1830270534a45fd9708dba3a7652d%7Cafc1818e7b68485689 13201b9396c4fc%7C1%7C0%7C638283711594119946%7CUnknown%7CTWFpbGZsb3d8e yJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3 000%7C%7C%7C&sdata=4GaP2jVvIMMFXi1f5nWMRt3KF6F723rPZUbNuDzyU%2Bw%3D&r eserved=0
Greetings, Silvan
-- Daniel-Constantin Mierla -- http://www.a/ sipto.com%2F&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1830270534a45fd 9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C6382837115 94119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=8fi7fgZqNKMbb67Vm7 X0TlI1B5BGk8QzS5kiiE3WvPw%3D&reserved=0 http://www.t/ witter.com%2Fmiconda&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1830270 534a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C63 8283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV 2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=5g6rGiCfkG Yrd7l5XnJdjqNbzL27pnax3WdoSksHThU%3D&reserved=0 -- http://www.l/ inkedin.com%2Fin%2Fmiconda&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd1 830270534a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C 0%7C638283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJ QIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=8tVs EpkONunTFeq1KJdn4FPCXWUhm2vEpIsOmAuEMSU%3D&reserved=0 Kamailio World Conference - http://www.k/ amailioworld.com%2F&data=05%7C01%7Cbkaufman%40bcmone.com%7C5cd18302705 34a45fd9708dba3a7652d%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C638 283711594119946%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2 luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=PjA3NmvxI9E 7l88a7nux21mHdnRs0ajPDxUTShKrvds%3D&reserved=0
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