audio problem and calls drop after a while on asterisk based telephony system

[gemini]

hi,

I have an asterisk based telephony system running on centos 6.x ( esxi ) , there are IP PBX, mediant on the system.

there is a problem on calls, calls drop after a while, cli says restransmission, provider warning, some of user blocked by the system , system runs sometimes slowly too, we can not send fax too, smtp mail does not work sometimes.

any idea? firewall, nat, configuration solutions would be appriciated too.

b. regards

 

[Adrian Fretwell]

With all of those different things giving you problems, there must be an underlying cause; you may have some intermittent network connectivity issues or a general poor or slow connection. I would look at the network for problems, there are lots of Linux tools out there to help you.

 

[gemini]

any tools you suggest me?

regards

 

[Adrian Fretwell]

Judging by the questions you ask, it sounds like you have a steep learning curve ahead of you but I will try to help.
Here are a few tools you may find helpful (there are many, many more), but you will need to gain knowledge of the switches to use, and how to interpret any results:

ping: check if target host is accessible, you can also change the packet size to stress the connection a little.
nmap: information about what’s running on network hosts, what ports are open or filtered.
ngrep: inspect data packets, very useful for text based protocols like SIP.
tcpdump: analyse traffic to or from to your server or capture traffic between two or more endpoints, pcap files can be viewed in Wireshark.
wireshark: see tcpdump.
iperf: assess the bandwidth available between two computers.
netcat: send and receive network traffic.
dig: diagnostics for all DNS related issues.
netstat: displays network connections for the Transmission Control Protocol, routing tables, and a number of network interface and network protocol statistics.

And closer to home...

ifconfig: get information about network interfaces (now replaced by the ip command in some distributions, but still available to install).
dmesg: get information of how the O/S kernel sees your hardware and drivers.
iptables: examine firewall rules.

The command I probably use the most in diagnosing SIP issues is ngrep -W byline -td any . port 5060
This will capture all SIP packages on 5060 on all interfaces

I hope this gives you a start, you will probably have some reading to do

 

[gemini]

thanks for your response, sometimes system gives on asterisk cli : retransmission warning and provider can not initialize itself.
on the network , it gives : there is rtnetlink files already
and If I want to send mail, it says it sent , but it did not.
thank you helpful messages.I will look.

yours sincerily

 

[gemini]

hi again,
some dmesg outputs that I wonder:

i801_smbus 0000:00:1f.3: can't derive routing for PCI INT C
ERST: Error Record Serialization Table (ERST) support is initialized.
pci 0000:16:00.0: can't claim BAR 6 [mem 0xfffe0000-0xffffffff pref]: no compatible bridge window
pci 0000:16:00.0: [Firmware Bug]: VPD access disabled
audit: initializing netlink socket (disabled)
[Firmware Bug]: No valid trip found

my hosts file :

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6

do I need add my host here ?

nmap sT ip gave 587 and some ports closed ?
I can not open it via iptables , why does system not take iptables rules? what is overriding it?

netstat results for 25
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 ::1:25 :::* LISTEN

emailserver does not work properly and isp follow extra very long path for dns records. there are at least extra 3 hops.
b.regards,

regards,