19 May
2020
19 May
'20
7:42 p.m.
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts dmq-ng.services.domain.com
172.30.154.189 dmq-ng.services.domain.com
172.17.130.13 dmq-ng.services.domain.com
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090")
In another case, where the resolving IPs for the DMQ service hostname were
listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the getent
command.
Doesn't kamailio use nss for hostname resolution? Am I missing something
else? Thanks!
BR,
George
19 May
19 May
8:23 p.m.
You are correct that Kamailio does not use the libc resolver /
libresolv, but rather its own resolver, which ignores /etc/hosts.
-- Alex
On 5/19/20 10:42 AM, George Diamantopoulos wrote:
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
172.17.130.13 dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>")
In another case, where the resolving IPs for the DMQ service hostname
were listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the
getent command.
Doesn't kamailio use nss for hostname resolution? Am I missing something
else? Thanks!
BR,
George
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
8:48 p.m.
Hello,
worth to clarify that Kamailio doesn't implement a dns resolver from
scratch, it still uses the functions from libc. It only does caching and
try to use cashing records first.
By default, the following dns functions are used internally when the
cache doesn't have the record already -- they are set in the dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the /etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
You are correct that Kamailio does not use the libc
resolver /
libresolv, but rather its own resolver, which ignores /etc/hosts.
-- Alex
On 5/19/20 10:42 AM, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>")
In another case, where the resolving IPs for the DMQ service hostname
were listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the
getent command.
Doesn't kamailio use nss for hostname resolution? Am I missing
something else? Thanks!
BR,
George
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
9:42 p.m.
A quick follow up as I found quite interesting that nowadays *BSDs allow
specifying order of lookup in resolv.conf to include the hosts file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
Hello,
worth to clarify that Kamailio doesn't implement a dns resolver from
scratch, it still uses the functions from libc. It only does caching and
try to use cashing records first.
By default, the following dns functions are used internally when the
cache doesn't have the record already -- they are set in the dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the /etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
You are correct that Kamailio does not use the
libc resolver /
libresolv, but rather its own resolver, which ignores /etc/hosts.
-- Alex
On 5/19/20 10:42 AM, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>")
In another case, where the resolving IPs for the DMQ service hostname
were listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the
getent command.
Doesn't kamailio use nss for hostname resolution? Am I missing
something else? Thanks!
BR,
George
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
20 May
20 May
10:35 p.m.
Hello all,
Thank you for your enlightening answers. I ended up creating DNS entries
anyway, so it's all good now. use_dns_cache=no sounded a little scary :-).
BR.
George
On Tue, 19 May 2020 at 19:44, Daniel-Constantin Mierla <miconda(a)gmail.com>
wrote:
A quick follow up as I found quite interesting that
nowadays *BSDs allow
specifying order of lookup in resolv.conf to include the hosts file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
Hello,
worth to clarify that Kamailio doesn't implement a dns resolver from
scratch, it still uses the functions from libc. It only does caching and
try to use cashing records first.
By default, the following dns functions are used internally when the
cache doesn't have the record already -- they are set in the dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the /etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
You are correct that Kamailio does not use the
libc resolver /
libresolv, but rather its own resolver, which ignores /etc/hosts.
-- Alex
On 5/19/20 10:42 AM, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>")
In another case, where the resolving IPs for the DMQ service hostname
were listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the
getent command.
Doesn't kamailio use nss for hostname resolution? Am I missing
something else? Thanks!
BR,
George
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
11:56 p.m.
Hello,
having use_dns_cache=no is not that bad if you have a local dns cache
application pointed by /etc/resolv.conf, provided that you do not need
srv based load balancing.
Not being the developer of dns resolving part in kamailio and the dns
cache, I investigated a bit and practically the /etc/hosts is the
pre-dns way of associating domains to ip addresses, without ttl and
other attributes specific to dns records. That seems the reason the libc
dns related functions do not use it implicitly, thus also not reflected
inside kamailio dns caching.
Now, you can add records to kamailio dns cache via rpc commands, which
can be done also from config using jsonrpc_exec() from jsonrpcs module
(e.g., using event_route[htable:mod-init] before sip traffic is
handled). The command should be liked:
kamctl rpc dns.add_a domain ttl ipaddr flags
The flags can be 1 to add it as a bad record (blacklisted domain) or 2
to add it as permanent record (do not expire). You can use dns.add_aaaa
for ipv6.
Actually I am now thinking to add the possibility to add to dns cache
via modparam of ipops module, to make it easier overall.
Cheers,
Daniel
On 20.05.20 19:35, George Diamantopoulos wrote:
Hello all,
Thank you for your enlightening answers. I ended up creating DNS
entries anyway, so it's all good now. use_dns_cache=no sounded a
little scary :-).
BR.
George
On Tue, 19 May 2020 at 19:44, Daniel-Constantin Mierla
<miconda(a)gmail.com <mailto:miconda@gmail.com>> wrote:
A quick follow up as I found quite interesting that nowadays *BSDs
allow
specifying order of lookup in resolv.conf to include the hosts
file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
--
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>
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
Hello,
worth to clarify that Kamailio doesn't implement a dns resolver from
scratch, it still uses the functions from libc. It only does
caching and
try to use cashing records first.
By default, the following dns functions are used internally when the
cache doesn't have the record already -- they are set in the
dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the
/etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
> You are correct that Kamailio does not use the libc resolver /
> libresolv, but rather its own resolver, which ignores /etc/hosts.
>
> -- Alex
>
> On 5/19/20 10:42 AM, George Diamantopoulos wrote:
>> Hello all,
>>
>> I've come across this today when trying to setup DMQ replication:
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
>> root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
>> {
>> host: 172.30.154.189
>> port: 5090
>> resolved_ip: 172.30.154.189
>> status: active
>> last_notification: 0
>> local: 1
>> }
>> root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
>> dmq-ng.services.domain.com <http://dmq-ng.services.domain.com>
<http://dmq-ng.services.domain.com>
>> 172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>> 172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
>> /etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
>> "notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>
>>
<http://dmq-ng.services.domain.com:5090>")
>>
>> In another case, where the resolving IPs for the DMQ service
hostname
>> were listed as A records in DNS, this
worked as expected.
>> In this case, the second host of the DMQ group is not listed in
>> dmq.list_nodes, despite its being set in /etc/hosts, as shown
by the
getent command.
Doesn't kamailio use nss for hostname resolution? Am I missing
something else? Thanks!
BR,
George
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users Funding: https://www.paypal.me/dcmierla
--
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>
Funding: https://www.paypal.me/dcmierla
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)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(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
28 May
28 May
12:51 p.m.
For the records, I added a modparam to corex module which allows adding
A/AAAA records in the internal dns cache at startup. It could be useful
in this case as alternative for /etc/hostname entries, but also at least
for some testing scenarios to avoid updating records on dns server,
which may take time to propagate.
*
https://www.kamailio.org/docs/modules/devel/modules/corex.html#corex.p.dns_…
During runtime, there are rpc commands to add/remove records in the dns
cache.
Cheers,
Daniel
On 20.05.20 20:56, Daniel-Constantin Mierla wrote:
Hello,
having use_dns_cache=no is not that bad if you have a local dns cache
application pointed by /etc/resolv.conf, provided that you do not need
srv based load balancing.
Not being the developer of dns resolving part in kamailio and the dns
cache, I investigated a bit and practically the /etc/hosts is the
pre-dns way of associating domains to ip addresses, without ttl and
other attributes specific to dns records. That seems the reason the
libc dns related functions do not use it implicitly, thus also not
reflected inside kamailio dns caching.
Now, you can add records to kamailio dns cache via rpc commands, which
can be done also from config using jsonrpc_exec() from jsonrpcs module
(e.g., using event_route[htable:mod-init] before sip traffic is
handled). The command should be liked:
kamctl rpc dns.add_a domain ttl ipaddr flags
The flags can be 1 to add it as a bad record (blacklisted domain) or 2
to add it as permanent record (do not expire). You can use
dns.add_aaaa for ipv6.
Actually I am now thinking to add the possibility to add to dns cache
via modparam of ipops module, to make it easier overall.
Cheers,
Daniel
On 20.05.20 19:35, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
Hello all,
Thank you for your enlightening answers. I ended up creating DNS
entries anyway, so it's all good now. use_dns_cache=no sounded a
little scary :-).
BR.
George
On Tue, 19 May 2020 at 19:44, Daniel-Constantin Mierla
<miconda(a)gmail.com <mailto:miconda@gmail.com>> wrote:
A quick follow up as I found quite interesting that nowadays
*BSDs allow
specifying order of lookup in resolv.conf to include the hosts
file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda>
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla Hello,
worth to clarify that Kamailio doesn't implement a dns resolver
from
scratch, it still uses the functions from libc.
It only does
caching and
try to use cashing records first.
By default, the following dns functions are used internally
when the
cache doesn't have the record already -- they
are set in the
dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the
/etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
> You are correct that Kamailio does not use the libc resolver /
> libresolv, but rather its own resolver, which ignores /etc/hosts.
>
> -- Alex
>
> On 5/19/20 10:42 AM, George Diamantopoulos wrote:
>> Hello all,
>>
>> I've come across this today when trying to setup DMQ replication:
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
>> root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
>> {
>> host: 172.30.154.189
>> port: 5090
>> resolved_ip: 172.30.154.189
>> status: active
>> last_notification: 0
>> local: 1
>> }
>> root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
>> dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
<http://dmq-ng.services.domain.com>
>> 172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>> 172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
>> /etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
>> "notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>
>>
<http://dmq-ng.services.domain.com:5090>")
>>
>> In another case, where the resolving IPs for the DMQ service
hostname
>> were listed as A records in DNS, this
worked as expected.
>> In this case, the second host of the DMQ group is not listed in
>> dmq.list_nodes, despite its being set in /etc/hosts, as shown
by the
>
getent command.
>
> Doesn't kamailio use nss for hostname resolution? Am I missing
> something else? Thanks!
>
> BR,
> George
>
>
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>
--
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Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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--
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www.twitter.com/miconda <http://www.twitter.com/miconda> --
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Funding: https://www.paypal.me/dcmierla
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8:01 p.m.
Thank you for this, Daniel!
On 5/28/20 3:51 AM, Daniel-Constantin Mierla wrote:
For the records, I added a modparam to corex module
which allows adding
A/AAAA records in the internal dns cache at startup. It could be useful
in this case as alternative for /etc/hostname entries, but also at least
for some testing scenarios to avoid updating records on dns server,
which may take time to propagate.
*
https://www.kamailio.org/docs/modules/devel/modules/corex.html#corex.p.dns_…
During runtime, there are rpc commands to add/remove records in the dns
cache.
Cheers,
Daniel
On 20.05.20 20:56, Daniel-Constantin Mierla wrote:
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Hello,
having use_dns_cache=no is not that bad if you have a local dns cache
application pointed by /etc/resolv.conf, provided that you do not need
srv based load balancing.
Not being the developer of dns resolving part in kamailio and the dns
cache, I investigated a bit and practically the /etc/hosts is the
pre-dns way of associating domains to ip addresses, without ttl and
other attributes specific to dns records. That seems the reason the
libc dns related functions do not use it implicitly, thus also not
reflected inside kamailio dns caching.
Now, you can add records to kamailio dns cache via rpc commands, which
can be done also from config using jsonrpc_exec() from jsonrpcs module
(e.g., using event_route[htable:mod-init] before sip traffic is
handled). The command should be liked:
kamctl rpc dns.add_a domain ttl ipaddr flags
The flags can be 1 to add it as a bad record (blacklisted domain) or 2
to add it as permanent record (do not expire). You can use
dns.add_aaaa for ipv6.
Actually I am now thinking to add the possibility to add to dns cache
via modparam of ipops module, to make it easier overall.
Cheers,
Daniel
On 20.05.20 19:35, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla --www.asipto.com
www.twitter.com/miconda --www.linkedin.com/in/miconda
Funding:https://www.paypal.me/dcmierla
_______________________________________________
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Hello all,
Thank you for your enlightening answers. I ended up creating DNS
entries anyway, so it's all good now. use_dns_cache=no sounded a
little scary :-).
BR.
George
On Tue, 19 May 2020 at 19:44, Daniel-Constantin Mierla
<miconda(a)gmail.com <mailto:miconda@gmail.com>> wrote:
A quick follow up as I found quite interesting that nowadays
*BSDs allow
specifying order of lookup in resolv.conf to include the hosts
file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
--
Daniel-Constantin Mierla --www.asipto.com
www.twitter.com/miconda --www.linkedin.com/in/miconda
Funding:https://www.paypal.me/dcmierla Hello,
worth to clarify that Kamailio doesn't implement a dns resolver
from
scratch, it still uses the functions from libc.
It only does
caching and
try to use cashing records first.
By default, the following dns functions are used internally
when the
cache doesn't have the record already -- they
are set in the
dns_func
structure:
struct dns_func_t dns_func = {
res_init,
res_search,
gethostbyname,
#ifdef HAVE_GETHOSTBYNAME2
gethostbyname2
#else
NULL
#endif
};
So practically by leveraging res_init()/res_search() is relying on
/etc/resolv.conf to do DNS queries, which is not using the
/etc/hosts
(iirc). For more see:
* https://linux.die.net/man/3/res_search
Cheers,
Daniel
On 19.05.20 17:23, Alex Balashov wrote:
> You are correct that Kamailio does not use the libc resolver /
> libresolv, but rather its own resolver, which ignores /etc/hosts.
>
> -- Alex
>
> On 5/19/20 10:42 AM, George Diamantopoulos wrote:
>> Hello all,
>>
>> I've come across this today when trying to setup DMQ replication:
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
>> root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
>> {
>> host: 172.30.154.189
>> port: 5090
>> resolved_ip: 172.30.154.189
>> status: active
>> last_notification: 0
>> local: 1
>> }
>> root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
>> dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
<http://dmq-ng.services.domain.com>
>> 172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>> 172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>
<http://dmq-ng.services.domain.com>
>>
>> root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
>> /etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
>> "notification_address", "sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>
>>
<http://dmq-ng.services.domain.com:5090>")
>>
>> In another case, where the resolving IPs for the DMQ service
hostname
>> were listed as A records in DNS, this
worked as expected.
>> In this case, the second host of the DMQ group is not listed in
>> dmq.list_nodes, despite its being set in /etc/hosts, as shown
by the
>> getent command.
>>
>> Doesn't kamailio use nss for hostname resolution? Am I missing
>> something else? Thanks!
>>
>> BR,
>> George
>>
>>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users(a)lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>
> --
> Alex Balashov | Principal | Evariste Systems LLC
>
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
>
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users(a)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>
Funding: https://www.paypal.me/dcmierla
--
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>
Funding: https://www.paypal.me/dcmierla
_______________________________________________
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_______________________________________________
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8:58 p.m.
Welcome!
Btw, would anyone find it useful to be able to add also SRV records in
the cache via modparam? I did it for A/AAAA records, but should be easy
to extend for SRV...
Cheers,
Daniel
On 28.05.20 17:01, Alex Balashov wrote:
Thank you for this, Daniel!
On 5/28/20 3:51 AM, Daniel-Constantin Mierla wrote:
--
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Funding: https://www.paypal.me/dcmierla
For the records, I added a modparam to corex
module which allows
adding A/AAAA records in the internal dns cache at startup. It could
be useful in this case as alternative for /etc/hostname entries, but
also at least for some testing scenarios to avoid updating records on
dns server, which may take time to propagate.
*
https://www.kamailio.org/docs/modules/devel/modules/corex.html#corex.p.dns_…
During runtime, there are rpc commands to add/remove records in the
dns cache.
Cheers,
Daniel
On 20.05.20 20:56, Daniel-Constantin Mierla wrote:
--
Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hello,
having use_dns_cache=no is not that bad if you have a local dns
cache application pointed by /etc/resolv.conf, provided that you do
not need srv based load balancing.
Not being the developer of dns resolving part in kamailio and the
dns cache, I investigated a bit and practically the /etc/hosts is
the pre-dns way of associating domains to ip addresses, without ttl
and other attributes specific to dns records. That seems the reason
the libc dns related functions do not use it implicitly, thus also
not reflected inside kamailio dns caching.
Now, you can add records to kamailio dns cache via rpc commands,
which can be done also from config using jsonrpc_exec() from
jsonrpcs module (e.g., using event_route[htable:mod-init] before sip
traffic is handled). The command should be liked:
kamctl rpc dns.add_a domain ttl ipaddr flags
The flags can be 1 to add it as a bad record (blacklisted domain) or
2 to add it as permanent record (do not expire). You can use
dns.add_aaaa for ipv6.
Actually I am now thinking to add the possibility to add to dns
cache via modparam of ipops module, to make it easier overall.
Cheers,
Daniel
On 20.05.20 19:35, George Diamantopoulos wrote:
--
Daniel-Constantin Mierla --www.asipto.com
www.twitter.com/miconda --www.linkedin.com/in/miconda
Funding:https://www.paypal.me/dcmierla
_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users(a)lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hello all,
Thank you for your enlightening answers. I ended up creating DNS
entries anyway, so it's all good now. use_dns_cache=no sounded a
little scary :-).
BR.
George
On Tue, 19 May 2020 at 19:44, Daniel-Constantin Mierla
<miconda(a)gmail.com <mailto:miconda@gmail.com>> wrote:
A quick follow up as I found quite interesting that nowadays
*BSDs allow
specifying order of lookup in resolv.conf to include the hosts
file, but
that doesn't seem to be in Linux:
* https://man.openbsd.org/resolv.conf.5#lookup
Cheers,
Daniel
On 19.05.20 17:48, Daniel-Constantin Mierla wrote:
> Hello,
>
> worth to clarify that Kamailio doesn't implement a dns resolver
from
> scratch, it still uses the functions from libc. It only does
caching and
> try to use cashing records first.
>
> By default, the following dns functions are used internally
when the
> cache doesn't have the record already -- they are set in the
dns_func
> structure:
>
> struct dns_func_t dns_func = {
> res_init,
> res_search,
> gethostbyname,
> #ifdef HAVE_GETHOSTBYNAME2
> gethostbyname2
> #else
> NULL
> #endif
> };
>
> So practically by leveraging res_init()/res_search() is
relying on
> /etc/resolv.conf to do DNS queries, which is not using the
/etc/hosts
> (iirc). For more see:
>
> * https://linux.die.net/man/3/res_search
>
> Cheers,
> Daniel
>
> On 19.05.20 17:23, Alex Balashov wrote:
>> You are correct that Kamailio does not use the libc resolver /
>> libresolv, but rather its own resolver, which ignores
/etc/hosts.
>>
>> -- Alex
>>
>> On 5/19/20 10:42 AM, George Diamantopoulos wrote:
>>> Hello all,
>>>
>>> I've come across this today when trying to setup DMQ
replication:
>>>
>>> root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
>>> root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
>>> {
>>> host: 172.30.154.189
>>> port: 5090
>>> resolved_ip: 172.30.154.189
>>> status: active
>>> last_notification: 0
>>> local: 1
>>> }
>>> root@sbcpub0-stage-lhe0-cn1:/root# getent hosts
>>> dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
<http://dmq-ng.services.domain.com>
>>> 172.30.154.189 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>> <http://dmq-ng.services.domain.com>
>>> 172.17.130.13 dmq-ng.services.domain.com
<http://dmq-ng.services.domain.com>
>>> <http://dmq-ng.services.domain.com>
>>>
>>> root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
>>> /etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
>>> "notification_address",
"sip:dmq-ng.services.domain.com:5090
<http://dmq-ng.services.domain.com:5090>
>>> <http://dmq-ng.services.domain.com:5090>")
>>>
>>> In another case, where the resolving IPs for the DMQ service
hostname
>>> were listed as A records in DNS, this worked as expected.
>>> In this case, the second host of the DMQ group is not
listed in
>>> dmq.list_nodes, despite its being set in /etc/hosts, as shown
by the
>>> getent command.
>>>
>>> Doesn't kamailio use nss for hostname resolution? Am I missing
>>> something else? Thanks!
>>>
>>> BR,
>>> George
>>>
>>>
>>> _______________________________________________
>>> Kamailio (SER) - Users Mailing List
>>> sr-users(a)lists.kamailio.org
<mailto:sr-users@lists.kamailio.org>
>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>
>> --
>> Alex Balashov | Principal | Evariste Systems LLC
>>
>> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
>> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
>>
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users(a)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>
> Funding: https://www.paypal.me/dcmierla
>
-- 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>
Funding: https://www.paypal.me/dcmierla
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--
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www.twitter.com/miconda --www.linkedin.com/in/miconda
Funding:https://www.paypal.me/dcmierla 
19 May
19 May
8:28 p.m.
Hi George,
if you are wondering how to switch it to system resolver, set global options
use_dns_cache=no, but per my understanding this may have performance impact.
On 19.05.2020, at 16:42, George Diamantopoulos
<georgediam(a)gmail.com> wrote:
Doesn't kamailio use nss for hostname resolution? Am I missing something else?
Thanks!
BR,
Andrew
25 May
25 May
9:27 p.m.
Hi George,
you could set the used dns server in Kamailio to only one and setup an
dnsmasq for example that is number one in /etc/resolve.conf.
dnsmasq can handle /etc/hosts as source or you combine your dns domain with
upstream dnserver (so dnsmasq ask for domain foo your server baa).
If you turn on dns request logging in dnsmasq you see what your server is
doing / asking for.
Just as an tricky hack. I needed that for one carrier that used split brain
dns in public.
Cheers
Karsten
George Diamantopoulos <georgediam(a)gmail.com> schrieb am Di., 19. Mai 2020,
16:43:
Hello all,
I've come across this today when trying to setup DMQ replication:
root@sbcpub0-stage-lhe0-cn1:/root# systemctl restart kamailio
root@sbcpub0-stage-lhe0-cn1:/root# kamcmd dmq.list_nodes
{
host: 172.30.154.189
port: 5090
resolved_ip: 172.30.154.189
status: active
last_notification: 0
local: 1
}
root@sbcpub0-stage-lhe0-cn1:/root# getent hosts dmq-ng.services.domain.com
172.30.154.189 dmq-ng.services.domain.com
172.17.130.13 dmq-ng.services.domain.com
root@sbcpub0-stage-lhe0-cn1:/root# grep dmq-ng /etc/kamailio/*
/etc/kamailio/kamailio-module-params.cfg:modparam("dmq",
"notification_address", "sip:dmq-ng.services.domain.com:5090")
In another case, where the resolving IPs for the DMQ service hostname were
listed as A records in DNS, this worked as expected.
In this case, the second host of the DMQ group is not listed in
dmq.list_nodes, despite its being set in /etc/hosts, as shown by the getent
command.
Doesn't kamailio use nss for hostname resolution? Am I missing something
else? Thanks!
BR,
George
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1430
days inactive
1439
days old
10 comments
5 participants
participants (5)
-
Alex Balashov -
Andrew Pogrebennyk -
Daniel-Constantin Mierla -
George Diamantopoulos -
Karsten Horsmann