26 Jun
2003
26 Jun
'03
8:22 p.m.
When does SER perform DNS lookups? Is it a matter of how the entry is
made in the ser.cfg? I ask because one of our customers changed their
DNS servers and the SER proxy was not updated. In the ser.cfg all
routing is done by IP (or I had thought it was). However, the site
started experiencing some very odd call drops and after updating the
resolv.conf on the proxy server with the proper DNS servers (one of them
had changed) everything was fine.
Should IP address entries be quoted or non-quoted? Does the presence of
the quotes cause a DNS lookup even though the item in them is purely
numeric (i.e. "162.128.33.54"). Is there a way to avoid the DNS
lookups?
--
Jamin W. Collins
Linux is not The Answer. Yes is the answer. Linux is The Question. - Neo
26 Jun
26 Jun
8:03 p.m.
On Jun 26, 2003 at 12:22, Jamin W. Collins <jcollins(a)asgardsrealm.net> wrote:
When does SER perform DNS lookups? Is it a matter of
how the entry is
made in the ser.cfg? I ask because one of our customers changed their
DNS servers and the SER proxy was not updated. In the ser.cfg all
routing is done by IP (or I had thought it was). However, the site
started experiencing some very odd call drops and after updating the
resolv.conf on the proxy server with the proper DNS servers (one of them
had changed) everything was fine.
DNS lookups for the addresses in ser.cfg are performed only once, on ser
startup immediately after reading the cfg. file.
Should IP address entries be quoted or non-quoted?
It doesn't matter (they have
to be quoted for modules functions, like
t_relay_to, they can be unquoted for forward*(...) ).
Does the presence of
the quotes cause a DNS lookup even though the item in them is purely
numeric (i.e. "162.128.33.54").
No. Internal ser resolve functions will
be called, but in the default
compilation (with -DDNS_IP_HACK added) they will recognize ipv4 & ipv6
addresses and no dns lookup will be performed.
Runtime DNS lookups for requests are performed only for forward (uri:host),
t_relay() and other uri involving forwarding functions.
Andrei
10 p.m.
On Thu, Jun 26, 2003 at 08:03:59PM +0200, Andrei Pelinescu-Onciul wrote:
Runtime DNS lookups for requests are performed only
for forward
(uri:host), t_relay() and other uri involving forwarding functions.
That would appear to have been it. Even though the uri:host was purely
IP. But the odd part is that it would stay up for a few seconds and
then the remote end would tear it down.
Correcting the system's DNS server entries (one of them had been
replaced with a new server) corrected the problem. Just found it very
odd since all the references in the config were by IP not name.
--
Jamin W. Collins
Linux is not The Answer. Yes is the answer. Linux is The Question. - Neo
10:26 p.m.
Andrei Pelinescu-Onciul wrote:
On Jun 26, 2003 at 12:22, Jamin W. Collins
<jcollins(a)asgardsrealm.net> wrote:
Not quite. Run-time reverse DNS lookups also performed when you are
doing comparisons involving src_ip.
-Maxim
When does SER perform DNS lookups? Is it a matter
of how the entry is
made in the ser.cfg? I ask because one of our customers changed their
DNS servers and the SER proxy was not updated. In the ser.cfg all
routing is done by IP (or I had thought it was). However, the site
started experiencing some very odd call drops and after updating the
resolv.conf on the proxy server with the proper DNS servers (one of them
had changed) everything was fine.
DNS lookups for the addresses in ser.cfg are performed only once, on ser
startup immediately after reading the cfg. file.
Should IP address entries be quoted or non-quoted?
It doesn't matter (they have to be quoted for modules functions, like
t_relay_to, they can be unquoted for forward*(...) ).
Does the presence of
the quotes cause a DNS lookup even though the item in them is purely
numeric (i.e. "162.128.33.54").
No. Internal ser resolve functions will be called, but in the default
compilation (with -DDNS_IP_HACK added) they will recognize ipv4 & ipv6
addresses and no dns lookup will be performed.
Runtime DNS lookups for requests are performed only for forward (uri:host),
t_relay() and other uri involving forwarding functions.
27 Jun
27 Jun
1:09 p.m.
On Jun 26, 2003 at 23:26, Maxim Sobolev <sobomax(a)portaone.com> wrote:
Andrei Pelinescu-Onciul wrote:
Yes, you are right. I forgot about those.
In ser 0.8.10 comparisons with source/dest ip will always involve a rev.
dns lookup if the operand is enclosed in quotes (e.g. src_ip=="1.2.3.4"
as oposed to src_ip==1.2.3.4 or src_ip==1.2.3.4/32 which will not
involve dns lookups).
In ser 0.8.11pre* things are a little better: if an ip addr. is in
quotes it will first be compared to src_ip without any dns lookups, but
if it does not match, a rev dns on src_ip will be performed and each
alias in the result will be compared with the operand.
So if you use ip addresses in comparisons, use them without quotes,
things will run mutch faster.
Andrei
On Jun 26, 2003 at 12:22, Jamin W. Collins
<jcollins(a)asgardsrealm.net>
wrote:
Not quite. Run-time reverse DNS lookups also performed when you are
doing comparisons involving src_ip. When does SER perform DNS lookups? Is it a matter
of how the entry is
made in the ser.cfg? I ask because one of our customers changed their
DNS servers and the SER proxy was not updated. In the ser.cfg all
routing is done by IP (or I had thought it was). However, the site
started experiencing some very odd call drops and after updating the
resolv.conf on the proxy server with the proper DNS servers (one of them
had changed) everything was fine.
DNS lookups for the addresses in ser.cfg are performed only once, on ser
startup immediately after reading the cfg. file.
Should IP address entries be quoted or non-quoted?
It doesn't matter (they have to be quoted for modules functions, like
t_relay_to, they can be unquoted for forward*(...) ).
Does the presence of
the quotes cause a DNS lookup even though the item in them is purely
numeric (i.e. "162.128.33.54").
No. Internal ser resolve functions will be called, but in the default
compilation (with -DDNS_IP_HACK added) they will recognize ipv4 & ipv6
addresses and no dns lookup will be performed.
Runtime DNS lookups for requests are performed only for forward (uri:host),
t_relay() and other uri involving forwarding functions.
7618
days inactive
7619
days old
4 comments
3 participants
participants (3)
-
Andrei Pelinescu-Onciul -
Jamin W. Collins -
Maxim Sobolev