Blocking SMTP connections - Revision history

Cocodude: /* Rate Limiting */

2017-03-23T13:44:20Z

Rate Limiting

← Older revision		Revision as of 13:44, 23 March 2017
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	If you want to reduce their SMTP limits to around 1Mbit per second (66 packets at ~1500 bytes per packet), use the following commands:		If you want to reduce their SMTP limits to around 1Mbit per second (66 packets at ~1500 bytes per packet), use the following commands:

	iptables -t mangle -A POSTROUTING -s <IP ADDRESS> -p tcp --~~destination~~-~~port~~ 25 -m limit --limit 66/sec -j ACCEPT		iptables -t mangle -A POSTROUTING -s <IP ADDRESS> -p tcp -m multiport --dports 25,465 -m limit --limit 66/sec -j ACCEPT
	iptables -t mangle -A POSTROUTING -s <IP ADDRESS> -p tcp --~~destination~~-~~port~~ 25 -j DROP		iptables -t mangle -A POSTROUTING -s <IP ADDRESS> -p tcp -m multiport --dports 25,465 -j DROP

	To unblock, just use the -D rules:		To unblock, just use the -D rules:

	iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --~~destination~~-~~port~~ 25 -m limit --limit 66/sec -j ACCEPT		iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp -m multiport --dports 25,465 -m limit --limit 66/sec -j ACCEPT
	iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --~~destination~~-~~port~~ 25 -j DROP		iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp -m multiport --dports 25,465 -j DROP

Cocodude at 20:02, 20 April 2013

2013-04-20T20:02:20Z

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 If a VPS user has been found to be spamming other users, you can block them temporarily from accessing SMTP ports by issuing commands similar to the following on the node that their VPS is situated on:
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    iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --source-port 25 -j DROP
    iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --destination-port 25 -j DROP

Cocodude at 13:29, 27 July 2012

2012-07-27T13:29:45Z

← Older revision		Revision as of 13:29, 27 July 2012
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	iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --source-port 25 -j DROP		iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --source-port 25 -j DROP
	iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --destination-port 25 -j DROP		iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --destination-port 25 -j DROP

			To unblock, just use the -D rules:

			iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --source-port 25 -j DROP
			iptables -t mangle -D POSTROUTING -s <IP ADDRESS> -p tcp --destination-port 25 -j DROP

Cocodude: Created page with "If a VPS user has been found to be spamming other users, you can block them temporarily from accessing SMTP ports by issuing commands similar to the following on the node that th..."

2012-07-23T16:01:10Z

Created page with "If a VPS user has been found to be spamming other users, you can block them temporarily from accessing SMTP ports by issuing commands similar to the following on the node that th..."

New page

If a VPS user has been found to be spamming other users, you can block them temporarily from accessing SMTP ports by issuing commands similar to the following on the node that their VPS is situated on:

iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --source-port 25 -j DROP
iptables -t mangle -I POSTROUTING -s <IP ADDRESS> -p tcp --destination-port 25 -j DROP