dslreports logo
    All Forums Hot Topics Gallery
spc
Search Topic:
uniqs
47
share rss forum feed

nitzan
Premium,VIP
join:2008-02-27
kudos:8
reply to sokhapkin

Re: [Voip.ms] voip.ms compromised the privacy of Canadian teleph

said by sokhapkin:

Let me guess - you run something based on asterisk and have dnsmgr turned off. Am I right? It's a typical example of user error.

How often does Asterisk re-lookups a DNS entry for a server it's registering to? I'd think this would be based on the TTL for the DNS entry, is it not?

sokhapkin
Premium
join:2003-05-08
North Fort Myers, FL
No, it is a parameter in dnsmgr.conf.
--
»www.callwithus.com


XCOM
digitalnUll
Premium
join:2002-06-10
Spring, TX
Reviews:
·Vestalink
reply to nitzan
said by nitzan:

said by sokhapkin:

Let me guess - you run something based on asterisk and have dnsmgr turned off. Am I right? It's a typical example of user error.

How often does Asterisk re-lookups a DNS entry for a server it's registering to? I'd think this would be based on the TTL for the DNS entry, is it not?

You can specify the time it does the look up...

refreshinterval=3600
--
[nUll@dcypher ~]$

nitzan
Premium,VIP
join:2008-02-27
kudos:8
reply to sokhapkin
I realize that, but if dnsmgr is turned off (it's off by default at least on some versions) - wouldn't Asterisk re-lookup a DNS entry after it's expired (TTL) anyway?? if not then that's a serious design flaw...

sokhapkin
Premium
join:2003-05-08
North Fort Myers, FL

1 recommendation

said by nitzan:

I realize that, but if dnsmgr is turned off (it's off by default at least on some versions) - wouldn't Asterisk re-lookup a DNS entry after it's expired (TTL) anyway?? if not then that's a serious design flaw...

No, it will not re-lookup! When dnsmgr is off asterisk does name resolution once and forever.
--
»www.callwithus.com

nitzan
Premium,VIP
join:2008-02-27
kudos:8
said by sokhapkin:

No, it will not re-lookup! When dnsmgr is off asterisk does name resolution once and forever.

Interesting. That makes zero sense. The whole point of having a TTL is to have lookups refreshed when they expire... oh well, good to know.

ConstantineM

join:2011-09-02
San Jose, CA

config files and name resolution

said by nitzan:

said by sokhapkin:

No, it will not re-lookup! When dnsmgr is off asterisk does name resolution once and forever.

Interesting. That makes zero sense. The whole point of having a TTL is to have lookups refreshed when they expire... oh well, good to know.

What, in your opinion, would then be the point of the supposed dnsmgr?

It actually makes perfect sense when you think about it from the programming perspective: name resolution is only done when you load the config, so TTL plays no role whatsoever.

Basically, such a setup is only one step further from hardcoding IP-addresses by hand. A lot of system tools are designed like this (for one, firewalls come to mind, and ping, and ssh, and basically every other simple tool).