[asterisk-bugs] [JIRA] (ASTERISK-26735) res_pjsip_endpoint_identifier_ip: "srv_lookups" after match in .conf has no effect

[Michael Maier (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-26735?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=234799#comment-234799 ] 

Michael Maier commented on ASTERISK-26735:
------------------------------------------

To be more clear:

pjsip distinguishes between two modes: resolving the DNS name "via" dig tel.t-online.de or dig _sip._udp.tel.t-online.de SRV. This is done based on missing or not missing port after the domain information (tel.t-online.de:5060 vs. tel.t-online.de (-> SRV)).

W/o the mentioned patch, asterisk uses as match entry *always* the result of dig tel.t-online.de. W/ this patch, *always* the result of dig _sip._udp.tel.t-online.de SRV is used. In other words, the resolution doesn't cover the resolution mode used by pjsip. But Telekom does distinguish between these two modes and provides completely *different* ipaddresses.
Most probably it would be the easiest way, if you just use the target ipaddress from each REGISTER pjsip does. Or, if you don't know the mode pjsip uses, you should add the ipaddresses of both, dig tel.t-online.de and dig _sip._udp.tel.t-online.de SRV.

> res_pjsip_endpoint_identifier_ip: "srv_lookups" after match in .conf has no effect
> ----------------------------------------------------------------------------------
>
>                 Key: ASTERISK-26735
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-26735
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Resources/res_pjsip_endpoint_identifier_ip
>    Affects Versions: 13.13.1, 14.2.1
>         Environment: Centos 6 / 64bit
> FreePBX 13.0.190.7
>            Reporter: Michael Maier
>
> Using DNS SRV functionality with PJSIP leads to a wrong auto generated match entry, if DNS SRV results differ from standard resolution.
> Example:
> # dig tel.t-online.de
> ;; QUESTION SECTION:
> ;tel.t-online.de.               IN      A
> ;; ANSWER SECTION:
> tel.t-online.de.        584     IN      CNAME   ims.voip.t-ipnet.de.
> ims.voip.t-ipnet.de.    42403   IN      CNAME   ims001.voip.t-ipnet.de.
> ims001.voip.t-ipnet.de. 42403   IN      CNAME   s-epp-001.isp.t-ipnet.de.
> s-epp-001.isp.t-ipnet.de. 165   IN      A       217.0.23.4
> Asterisk builds the auto generated match entry on base of tel.t-online.de (217.0.23.4).
> The SRV entries are like this:
> # dig _sip._udp.tel.t-online.de SRV
> ;; QUESTION SECTION:
> ;_sip._udp.tel.t-online.de.     IN      SRV
> ;; ANSWER SECTION:
> _sip._udp.tel.t-online.de. 3600 IN      SRV     1 5 5060
> hh-epp-009.isp.t-ipnet.de.
> _sip._udp.tel.t-online.de. 3600 IN      SRV     0 5 5060
> b-epp-009.isp.t-ipnet.de.
> # dig b-epp-009.isp.t-ipnet.de
> ;; QUESTION SECTION:
> ;b-epp-009.isp.t-ipnet.de.      IN      A
> ;; ANSWER SECTION:
> b-epp-009.isp.t-ipnet.de. 595   IN      A       217.0.23.108
> # dig hh-epp-009.isp.t-ipnet.de
> ;; QUESTION SECTION:
> ;hh-epp-009.isp.t-ipnet.de.     IN      A
> ;; ANSWER SECTION:
> hh-epp-009.isp.t-ipnet.de. 246  IN      A       217.0.23.140
> PJSIP now registers e.g. to 217.0.23.108. This means, all incoming calls are sent from this IP - which is refused by asterisk, because asterisk uses the standard resolution of tel.t-online.de, which is 217.0.23.4 (in my case).
> Please do an auto generated match entry on base of the IP address PJSIP registered to.
> Workaround: 
> Manual definition of a huge Telekom net as match entry in pjsip.identify.conf (217.0.18.0/23,217.0.20.0/22,217.0.24.0/24) as nobody really knows which IPs Telekom will use.
> If used with stateful iptables rules not that big problem, nevertheless it would be good to have an accurate entry as it took me quite some time to get the reason!



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