Dropping 6th ICMP packets

[Razmir Masri Abdul Razak]

Hi All,

Can anyone explain to me why this is happening, is it the cable problem or something wrong the switch, this only happen when we ping our Cisco Callmanager. Why is the ping is like dropping every 6th packet. This is our local network and we are having problem with our phone registration because of this. (See attachement)

The callmanager is connected to 2960G switch and the core switch is Cisco 4500 series. All internal routing is done at core switch.

Thanks.

[paolo bevilacqua]

That is normal icmp rate limiting, as you would have found by searching before posting.

[Kasiraman S · Accepted solution]

Hi Razmir,

It is the firewall policy inside the CUCM doing this. But it is normal and is expected. If we try to ping this device from windows PC we cannot find this, normally IOS devices tend to send the ICMP at the faster rate. Cisco CUCM and other VOIP products(CUC) use a rate limit on their firewall and we can safely ignore this.

admin:utils firewall ipv4 list
***output Omitted***
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 icmptype 8 limit: avg 10/sec burst 5
LOG icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 8 limit: avg 1/min burst 5 LOG flags 0 level 4 prefix `ping flood '
DROP icmp -- 0.0.0.0/0 0.0.0.0/0 icmp type 8
***output Omitted***

Please mark this discussion answered if your are satisfy with the solution and do rate helpful post.

Thanks,

Kasi

[Razmir Masri Abdul Razak]

Hi,

Thank you for your response. It looks like something else is dropping our sccp packets. Some of our sccp IP Phone are unable to join the Call Manager. According to Cisco TAC after reviewing our packet sniffing result, it looks like something is dropping the packet since there is a lot of tcp retransmission on the phone side. At the moment, there are still no solution I will need to look into others possibilities..

Thanks guys..

[kenreeves]

Did this ever get answered for you? I am having the exact same issue with a handfull of SCCP phones. Work arounds was to migrate them to SIP. Please let me know. Thanks Ken

[Akhilesh Singh]

Ken,

Is there any firewall between the home IP phones and CUCM? (The
reason why I am asking because in  call manager 4.x, 5.x, 6.x all use SCCP
version 16, however call manager 7.X and 8.X Use SCCP version 17 and some
firewalls do not recognized version 17 at all, therefore it drops any Skinny
registration packets sent from the phone.)

Hope this answers your query why changing to SIP worked for you.

Akhi

[Gerson Fabian Morales Marin]

Hello,

You can verify if currently on your firewall is in use TCP  state bypass, this might sometimes is related to unregistered phones or issues when registering devices to your CUCM.

Link=http://www.cisco.com/c/en/us/td/docs/security/asa/asa82/configuration/guide/config/conns_tcpstatebypass.html

Regards,

Gerson

[Gerson Fabian Morales Marin]

Hello,

You can check if at the firewall you have configured SCCP inspection as this configuration normally makes SCCP to lose icmp messages finishing on unregistered phones or issues at the time of registering them.

[vishalkanojia.v]

i agree this post is helpful

[Daniel Cross]

Do you know if this behavior is replicated on Finesse Servers also?? I get the same result...... 

[joshua.gertig]

Really glad I stumbled on this old but still relevant post (still relevant on CUCM version 11.5 SU5). Thanks!

[carlos.collart]

our CUC and CUCCx that share the same host in the ESX5.0 had the same OS and share the same behaivor