ICMP redirects making TCP connection slow

[playerplease2]

HI Guys,

facing an interesting issue with ICMP redirect it seems.

In my office, we have a router with several Public IP address , among which these two: x.x.x.118 ( which I see from inside when running "what is my IP " in google) and x.x.x.115 which is used here below .

From the inside network, I want to connect via Remote Desktop the PC that is directly plugged into the router with allocated public IP x.x.x.115 .( accessible directly from the outside)
When try to RDP into it , the connection is ridiculously slow, if not stuck.

When I check the Wireshark capture of the TCP traffic ( on the Wifi connection in Subnet 10.1.10.x) , I see a lot of ICMP redirect .

Looking at the content, it seems to tell the HOST IP 10.1.10.61 that , in order to better reach x.x.x.115 , it should use gateway x.x.x.115 instead of its default 10.1.10.1 ?
It doesn't make any sense to me .
The HOST is windows and show default route 0.0.0.0/0 to 10.1.10.1

Find enclosed a screenshot of the Wireshark capture, it also happens for Ping . ( btw Ping have no real response time problem, and their TTL are all decrease by 1 hop only)

Any idea of why these ICMP redirects happen and is it the root cause of the RDP/TCP slowness problem here ?

My tracert from laptop shows :

Tracing route to X.X.X.115 [X.X.X.115]
over a maximum of 30 hops:

1 11 ms 6 ms 1 ms 10.1.10.1
2 9 ms 17 ms 7 ms x.x.x.115
Trace Complete

Thanks

Clement

[Georg Pauwen]

Hello,

what is the IP address of the PC you are trying to RDP into (source is 10.1.10.61 - destination ?) ?

Are you using NAT on the router ?

If possible, post the full configuration of the router...

[playerplease2]

HI, The destination address is x.x.x.115 , this is the public IP of the PC I'm  trying to RDP into.

It's true that there is a part of the config that I didn't quite get:

The router is doing NAT Overload  from its internal network 10.1.10.0/24 to an external address x.x.x.118.

If I configure a PC located on the inside network with IP address x.x.x.x115 ( x.x.x.x being the same vaues everywhere), how would the router NAT this ? I guess it would just not do it , and instead "passthrough" traffic from the external to the internal .

BTW: the PC configured with IP x.x.x.115 has its default gateway set x.x.x.118.

The RDP to x.x.x.155  from the outside works just fine, the ONLY problem is when doing RDP from the 10.1.10.x network into this public IP x.x.x.115.

[playerplease2]

the router is Comcast router , I don't have access to any CLI it's just a webGUI with some basic avanced commands..

[paul driver]

Hello

I am correct in saying that you are trying to RDP into a host via its natted external address and that host is residiing on the same internal vlan of the source?

res
Paul

[playerplease2]

thanks Paul, please see my answers above