Destination Nat problem ( RST trouble )

[dorbian]

Hi All,

Been wrecking my brain for a while now on why i’m having mayor NAT trouble.
I’ve setup DNAT for a couple of locations but they aren’t working reliably.
SSH works 40% of the time but RDP for instance 3% of the time.

Also HTTP and HTTPS natting is horrid.

When using TCPdump i see a large amounts of RST coming by but i have no clue why.

I disabled the incoming firewall to avoid that being a problem ( even tho it shouldn’t )

config file ( removed some info and it’s probably a slight mess, getting bald spots on my head from pulling my hair )
https://pastebin.com/yMCLPBBv

if someone is able to help figure out why i’m getting so many RST on so many different destinations that would be amazing

Cheers,

-D

[tjh]

Could it be an MTU problem?
You’re sure you’re not behind a CGNAT setup at your ISP?

[dorbian]

No CGNat, it’s a router inside a vmware esxi server, i cannot reliably reach the inside of the esxi server from the outside ( My local network ), apart from the ssh nat , have a similar esxi server one with a similar config that doesn’t have this problem, both of m are connected through a tunnel and that runs fine, also connectivity through the tunnel is fine.
MTU settings are the same for both.

also as a note i’m using the latest rolling release ( upgraded as i figured it might have been a bug that was fixed )

[dorbian]

Think i fixed it, i initially used e1000 interfaces, moved them over to vmxnet3 and i’m not seeing any of the previous behavior.

[tjh]

Well that’s random. I still think it sounds like an MTU or fowarding type issue, very interesting that e1000 caused it.
I’ve always used the virtual NICs instead of emulated hardware ones.

Thanks for coming back though and clarifying how you fixed it!