cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements

Welcome to the Cisco Small Business Community

Have a question? Click on a topic board below to get started in the community.
Get the latest news in this issue of the Cisco Small Business Monthly Newsletter

458
Views
0
Helpful
2
Replies
Highlighted
Beginner

ASA issue - Persistant Connections ?

Hello,

I had a strange issue over that i can't figure out the cause, looking for feedback

 

Details - I had to power down a pair of switches for battery work, when powered them back on, i noticed our phones didn't register. We use a cloud provided service, so the phones register over the internet. When i ran a ping to the cloud IP, if failed, all other connections were working, routing was checked, it was exclusive to this one address.

 

After about 15 minutes, I could reach the address and the phones registered. 

 

I opened a TAC case, but had to close since the issue resolved itself.

2 REPLIES 2
Highlighted
Rising star

Hi, I suspect that the provider use a DoS protection system with dynamics blacklist ACL.

Some devices usa a blacklist to  protect itself form potential attacks.

I suspect that in your profile you have a maximum concurrent registration allowed in a certain time.

If the provider receive a lot of simultaneous registration requests from a single IP, it can consider this as a potential attack a put the IP in a blacklist from e.g. 10 or 15 minutes.

I'm not sure of this but can explain why the IP of cloud provider was unreachable.

Please, ask to your provider and check if they have this protection system configured.

 

Regards.

Highlighted

That's a great thought, I haven't thought about that, I will check with my vendor on this.

 

Thanks!