RV345 port forwarding not working for re-entrant traffic

[mmoerman]

Hi,

I seem to run in a bit of a problem with re-entrant traffic on the RV345. 

My setup is fairly simple some VLANs and the latest firmware 1.0.03.15. 

I hav a mail server behind the RV345 on one of the VLANs. I have port address translation setup to route mail traffic to that server. I have a static IP.

When I connect externally from the internet to my mailserver everything works fine.

When I am inside my network and try to connect to the mailserver it doesn't work.

The DNS entry that I use bth internally and externally are the same entry. So it seems that the router is having an issue doing this.

Internal network -> router -> edge of router -> router (port translation) -> e-mail server.

Anyone have any ideas? Thanks for the help.

[JRodr]

I dont know if this helps.

It seems you are doing Hairpinning (https://en.wikipedia.org/wiki/Hairpinning)

The release notes for the latest firmware version have the following information:

CSCvp01703
Description: RV34x: NAT hairpinning doesn't work when the InterVLAN Routing is disabled.
Workaround: Create firewall access rule to permit the traffic to the particular LAN server.

If this does not solve the problem you may be able to work aroud by using split DNS

External DNS (used outside) will resolve to the external IP Address.

Internal DNS (used only in the internal network) will resolve to the internal IP Address.

Your internal clients will need to use the internal DNS.

[M.Bag]

Hello,

did you solve the problem?

I have the same problem with a RV340.

In my case InterVlan Routing is enabled, but it doesn't solve the problem.

You suggest to split DNS for internal and external users.

But... what kind of DNS should use an internal user?

I tried many DNS but hairpin doesn't work with this router.

Thank you.