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mafiosa
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EOIP not working behind 1:1 nat

Fri Oct 23, 2020 11:57 am

Hello my ISP provides me public ip via 1:1 NAT, gre and all vpns work fine but EOIP doesn't work. Can someone confirm me that EOIP works behind nat or not? Please, it is urgent as I have to remove mikrotik from my network if it doesn't
 
sindy
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Re: EOIP not working behind 1:1 nat

Fri Oct 23, 2020 1:47 pm

If set up properly, there is no reason why EoIP shouldn't work across a NAT, as EoIP looks like GRE from outside.

If EoIP doesn't work, you can use L2TP with BCP for L2 tunneling instead - since you have EoIP, I guess you have a Mikrotik at both ends.

Show the complete configuration exports from both ends. See my signature below for a hint how to obfuscate the sensitve infomration without breaking the internal dependencies between addresses, in your case it is very important.
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.
 
flameproof
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Re: EOIP not working behind 1:1 nat

Fri Oct 23, 2020 2:21 pm

EoIP is as simple to get working as it gets. I have created tunnels through NAT on a Mikrotik device, e.g. Mikrotik #1 -> [ NAT Mikrotik #2] -> Mikrotik #3. However, you need to be aware of MTU. Can you show your actual configuration?
 
mafiosa
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Re: EOIP not working behind 1:1 nat

Sun Nov 15, 2020 6:11 pm

EoIP is as simple to get working as it gets. I have created tunnels through NAT on a Mikrotik device, e.g. Mikrotik #1 -> [ NAT Mikrotik #2] -> Mikrotik #3. However, you need to be aware of MTU. Can you show your actual configuration?
Tried with no nathi on one side and 1:1 nat in the other. Reduced mtu to 1300 yet no luck.
 
sindy
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Re: EOIP not working behind 1:1 nat

Sun Nov 15, 2020 6:42 pm

Show me the configuration exports from both machines. The only reason why it may not work is firewall misconfiguration (or multiple devices using GRE behind the same NAT, but as you talk about 1:1 NAT, I assume it's not the case).
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.

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