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Cisco 857 Getting Slammed by SMTP traffic

Does anyone have recommendations for how I can block smtp traffic having the router completely disregard instead of having to spend time every second of every day dropping traffic attempted to connect in via smtp from spammers all around the world?

Just last week alone we had 400,000 spam messages attempted to be sent through our IP. If this many messages are coming in or rather attempting to come in, there has to be a way other than setting a rule to only accept smtp traffic from a specific IP in the case of filtering which we are utilizing.

Any ideas would be greatly appreciated. I am considering purchasing a new bank of addresses to resolve this problem but I think that it is only a matter of time before we see this issue again.


Re: Cisco 857 Getting Slammed by SMTP traffic

Usually ISPs take care of this.But we could try to configure an Extended Access list for SMTP traffic allowing only the ip addresses that is required.

Community Member

Re: Cisco 857 Getting Slammed by SMTP traffic

I am sorry, I should have mentioned that I am only allowing mail from a filtering service IP range.

Still, traffic is hitting the IP, not the server name. We might have to change our IP.

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