Hi
I've a question regarding skipped NAPTR records.
In our setup, we are using quite big DNS TTLs (860400). If there is an issue on the target server, the NAPTR record is marked as skipped "Mark to skip _sips._tcp.... NAPTR record due to all IPs are unreachable" until the TTL is expired. Since our TTLs are so big, the destination is no longer reachable during this time, even if the server is reachable again.
I've seen that I can set "dns_cache_max_ttl" to reduce the time, but this is of course for all cached DNS records. Is there a way to set how long a NAPTR record is skipped or disable the feature at all? Or maybe skip the NAPTR only for the current dialog or transaction?
Thanks for your help Best regards Mathias
Hello,
just deactivating NAPTR does not work for you? https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_try_naptr
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
Otherwise, you can of course always setup a local cache (dnsmasq, others) and add the needed records with low TTLs there.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: Mathias Schneuwly via sr-users sr-users@lists.kamailio.org Sent: Montag, 10. März 2025 15:38 To: sr-users@lists.kamailio.org Cc: Mathias Schneuwly mathias@schneuwlys.ch Subject: [SR-Users] Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
I've a question regarding skipped NAPTR records.
In our setup, we are using quite big DNS TTLs (860400). If there is an issue on the target server, the NAPTR record is marked as skipped "Mark to skip _sips._tcp.... NAPTR record due to all IPs are unreachable" until the TTL is expired. Since our TTLs are so big, the destination is no longer reachable during this time, even if the server is reachable again.
I've seen that I can set "dns_cache_max_ttl" to reduce the time, but this is of course for all cached DNS records. Is there a way to set how long a NAPTR record is skipped or disable the feature at all? Or maybe skip the NAPTR only for the current dialog or transaction?
Thanks for your help Best regards Mathias
Thanks for the reply.
just deactivating NAPTR does not work for you?
No, our setup relies on NAPTR... That's why it is also fatal when the NAPTR is "burned" for a certain time.
Otherwise, you can of course always setup a local cache (dnsmasq, others)
We already use the internal DNS cache of Kamailio as we also use load balancing and fail over. As I understood from the documentation and testing, that doesn't work without the internal DNS cache.
You can also delete individual naptr entries in the internal cache with
RPC commands: dns.delete_naptr. The problem is, that I don't see with dns.view which record is marked to be skipped. DNS works and therefore all records look correct. To remove a certain record, I would need to write a service, which periodically iterates through the list and removes "burned" records. But for that, I somehow need to know which records are marked to be skipped. Is this somehow visible from outside?
Best regards Mathias
Am Di., 11. März 2025 um 09:15 Uhr schrieb Henning Westerholt <hw@gilawa.com
:
Hello,
ok, do you already tried to set the max cache TTL?
https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_cache_max_ttl
Cheers,
Henning
From: Mathias Schneuwly via sr-users sr-users@lists.kamailio.org Sent: Dienstag, 11. März 2025 10:05 To: sr-users@lists.kamailio.org Cc: Mathias Schneuwly mathias@schneuwlys.ch Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Thanks for the reply.
just deactivating NAPTR does not work for you?
No, our setup relies on NAPTR... That's why it is also fatal when the NAPTR is "burned" for a certain time.
Otherwise, you can of course always setup a local cache (dnsmasq, others)
We already use the internal DNS cache of Kamailio as we also use load balancing and fail over. As I understood from the documentation and testing, that doesn't work without the internal DNS cache.
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
The problem is, that I don't see with dns.view which record is marked to be skipped. DNS works and therefore all records look correct. To remove a certain record, I would need to write a service, which periodically iterates through the list and removes "burned" records. But for that, I somehow need to know which records are marked to be skipped. Is this somehow visible from outside?
Best regards Mathias
Am Di., 11. März 2025 um 09:15 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
just deactivating NAPTR does not work for you? https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_try_naptr
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
Otherwise, you can of course always setup a local cache (dnsmasq, others) and add the needed records with low TTLs there.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Montag, 10. März 2025 15:38 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
I've a question regarding skipped NAPTR records.
In our setup, we are using quite big DNS TTLs (860400). If there is an issue on the target server, the NAPTR record is marked as skipped "Mark to skip _sips._tcp.... NAPTR record due to all IPs are unreachable" until the TTL is expired. Since our TTLs are so big, the destination is no longer reachable during this time, even if the server is reachable again.
I've seen that I can set "dns_cache_max_ttl" to reduce the time, but this is of course for all cached DNS records. Is there a way to set how long a NAPTR record is skipped or disable the feature at all? Or maybe skip the NAPTR only for the current dialog or transaction?
Thanks for your help Best regards Mathias
Hi
ok, do you already tried to set the max cache TTL?
As written in the initial post, yes, I've tried that and with this option, I'm able to reduce the TTL. This would also be my work around if there is no better solution.
As this reduces the TTL for all records, I asked myself whether there is a possibility to just disable the skipping of the NAPTR so that I could still benefit from the longer TTLs and reduce the DNS queries and the overhead in the system.
Regards Mathias
Am Di., 11. März 2025 um 10:42 Uhr schrieb Henning Westerholt <hw@gilawa.com
:
Hello,
Sorry, I missed the comment about the max TTL time in the initial e-mail. Others might have more ideas, of course its also possible to extend the code and adding a new parameter for example. I personally would just adjust the TTL. If you are worried about DNS performance, you can always just use another local or central cache. In fact, on many linux systems you are already using a cache from systemd for all DNS records.
Cheers,
Henning
From: Mathias Schneuwly via sr-users sr-users@lists.kamailio.org Sent: Dienstag, 11. März 2025 10:52 To: sr-users@lists.kamailio.org Cc: Mathias Schneuwly mathias@schneuwlys.ch Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
ok, do you already tried to set the max cache TTL?
As written in the initial post, yes, I've tried that and with this option, I'm able to reduce the TTL. This would also be my work around if there is no better solution.
As this reduces the TTL for all records, I asked myself whether there is a possibility to just disable the skipping of the NAPTR so that I could still benefit from the longer TTLs and reduce the DNS queries and the overhead in the system.
Regards Mathias
Am Di., 11. März 2025 um 10:42 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
ok, do you already tried to set the max cache TTL?
https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_cache_max_ttl
Cheers,
Henning
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Dienstag, 11. März 2025 10:05 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Thanks for the reply.
just deactivating NAPTR does not work for you?
No, our setup relies on NAPTR... That's why it is also fatal when the NAPTR is "burned" for a certain time.
Otherwise, you can of course always setup a local cache (dnsmasq, others)
We already use the internal DNS cache of Kamailio as we also use load balancing and fail over. As I understood from the documentation and testing, that doesn't work without the internal DNS cache.
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
The problem is, that I don't see with dns.view which record is marked to be skipped. DNS works and therefore all records look correct. To remove a certain record, I would need to write a service, which periodically iterates through the list and removes "burned" records. But for that, I somehow need to know which records are marked to be skipped. Is this somehow visible from outside?
Best regards Mathias
Am Di., 11. März 2025 um 09:15 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
just deactivating NAPTR does not work for you? https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_try_naptr
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
Otherwise, you can of course always setup a local cache (dnsmasq, others) and add the needed records with low TTLs there.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Montag, 10. März 2025 15:38 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
I've a question regarding skipped NAPTR records.
In our setup, we are using quite big DNS TTLs (860400). If there is an issue on the target server, the NAPTR record is marked as skipped "Mark to skip _sips._tcp.... NAPTR record due to all IPs are unreachable" until the TTL is expired. Since our TTLs are so big, the destination is no longer reachable during this time, even if the server is reachable again.
I've seen that I can set "dns_cache_max_ttl" to reduce the time, but this is of course for all cached DNS records. Is there a way to set how long a NAPTR record is skipped or disable the feature at all? Or maybe skip the NAPTR only for the current dialog or transaction?
Thanks for your help Best regards Mathias
Thanks, I have to talk to the customer about which solution he prefers.
Meanwhile I opened a feature request ( https://github.com/kamailio/kamailio/issues/4174) to extend the output with rr_skip_record that at least the state is visible from outside.
Best regards Mathias
Am Di., 11. März 2025 um 11:15 Uhr schrieb Henning Westerholt <hw@gilawa.com
:
Hi Mathias,
sure. Thanks for the feature request, also including a patch. I can have a look later (if not somebody else picks it up in already).
Cheers,
Henning
From: Mathias Schneuwly via sr-users sr-users@lists.kamailio.org Sent: Dienstag, 11. März 2025 14:16 To: sr-users@lists.kamailio.org Cc: Mathias Schneuwly mathias@schneuwlys.ch Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Thanks, I have to talk to the customer about which solution he prefers.
Meanwhile I opened a feature request (https://github.com/kamailio/kamailio/issues/4174) to extend the output with rr_skip_record that at least the state is visible from outside.
Best regards Mathias
Am Di., 11. März 2025 um 11:15 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
Sorry, I missed the comment about the max TTL time in the initial e-mail. Others might have more ideas, of course its also possible to extend the code and adding a new parameter for example. I personally would just adjust the TTL. If you are worried about DNS performance, you can always just use another local or central cache. In fact, on many linux systems you are already using a cache from systemd for all DNS records.
Cheers,
Henning
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Dienstag, 11. März 2025 10:52 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
ok, do you already tried to set the max cache TTL?
As written in the initial post, yes, I've tried that and with this option, I'm able to reduce the TTL. This would also be my work around if there is no better solution.
As this reduces the TTL for all records, I asked myself whether there is a possibility to just disable the skipping of the NAPTR so that I could still benefit from the longer TTLs and reduce the DNS queries and the overhead in the system.
Regards Mathias
Am Di., 11. März 2025 um 10:42 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
ok, do you already tried to set the max cache TTL?
https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_cache_max_ttl
Cheers,
Henning
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Dienstag, 11. März 2025 10:05 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Re: Set TTL for skipped NAPTR record due to all IPs are unreachable
Thanks for the reply.
just deactivating NAPTR does not work for you?
No, our setup relies on NAPTR... That's why it is also fatal when the NAPTR is "burned" for a certain time.
Otherwise, you can of course always setup a local cache (dnsmasq, others)
We already use the internal DNS cache of Kamailio as we also use load balancing and fail over. As I understood from the documentation and testing, that doesn't work without the internal DNS cache.
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
The problem is, that I don't see with dns.view which record is marked to be skipped. DNS works and therefore all records look correct. To remove a certain record, I would need to write a service, which periodically iterates through the list and removes "burned" records. But for that, I somehow need to know which records are marked to be skipped. Is this somehow visible from outside?
Best regards Mathias
Am Di., 11. März 2025 um 09:15 Uhr schrieb Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com>: Hello,
just deactivating NAPTR does not work for you? https://www.kamailio.org/wikidocs/cookbooks/5.8.x/core/#dns_try_naptr
You can also delete individual naptr entries in the internal cache with RPC commands: dns.delete_naptr.
Otherwise, you can of course always setup a local cache (dnsmasq, others) and add the needed records with low TTLs there.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: Mathias Schneuwly via sr-users <sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org> Sent: Montag, 10. März 2025 15:38 To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Cc: Mathias Schneuwly <mathias@schneuwlys.chmailto:mathias@schneuwlys.ch> Subject: [SR-Users] Set TTL for skipped NAPTR record due to all IPs are unreachable
Hi
I've a question regarding skipped NAPTR records.
In our setup, we are using quite big DNS TTLs (860400). If there is an issue on the target server, the NAPTR record is marked as skipped "Mark to skip _sips._tcp.... NAPTR record due to all IPs are unreachable" until the TTL is expired. Since our TTLs are so big, the destination is no longer reachable during this time, even if the server is reachable again.
I've seen that I can set "dns_cache_max_ttl" to reduce the time, but this is of course for all cached DNS records. Is there a way to set how long a NAPTR record is skipped or disable the feature at all? Or maybe skip the NAPTR only for the current dialog or transaction?
Thanks for your help Best regards Mathias
-
Henning Westerholt -
Mathias Schneuwly