ANSWERED Strange connection problem

[HenningAlexander 0]

Hey,

I use multiple routers running asus merlin. Their traffic runs threw AirVPN. Now i have the problem, that the same konfiguration of VPN-Connection is working on one router properly and working not on another one.

This is the log from the not working router:

Dec 19 16:40:57 ovpn-client1[8898]: NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
Dec 19 16:40:57 ovpn-client1[8898]: TCP/UDP: Preserving recently used remote address: [AF_INET6]2a02:aa08:e000:4500:8b27:c782:5b23:5ea7:443
Dec 19 16:40:57 ovpn-client1[8898]: Socket Buffers: R=[87380->87380] S=[16384->16384]
Dec 19 16:40:57 ovpn-client1[8898]: Attempting to establish TCP connection with [AF_INET6]2a02:aa08:e000:4500:8b27:c782:5b23:5ea7:443
Dec 19 16:40:57 ovpn-client1[8898]: TCP: connect to [AF_INET6]2a02:aa08:e000:4500:8b27:c782:5b23:5ea7:443 failed: Cannot assign requested address
Dec 19 16:40:57 ovpn-client1[8898]: SIGUSR1[connection failed(soft),connection-failed] received, process restarting
Dec 19 16:40:57 ovpn-client1[8898]: Restart pause, 256 second(s)

Some ideas?


Thx

[Staff 10016]

@HenningAlexander

Hello!

Apparently the router or the implemented ovpn-client does not support IPv6. Please check. If the problem persists even when IPv6 is supported, what happens if you connect over IPv4?

Kind regards
 

[Air4141841 25]

I've never seen a TCP connecting try to use send and receive buffers.  I thought that was UDP only? 

[Staff 10016]

58 minutes ago, Air4141841 said:

I've never seen a TCP connecting try to use send and receive buffers.  I thought that was UDP only? 

Hello!

Socket buffers are essential both for TCP and UDP. In general it is a feature of sockets, in the OS TCP/IP stack in general, not something peculiar to OpenVPN. Buffers are essential in both connection-oriented sockets (TCP, SCTP...) and conectionless sockets (UDP). In general all sockets including raw sockets (those sockets which are used at IP layer) have two buffers, a read (aka receive) buffer and a write (aka send) buffer. A program (except for NIC kernel drivers ) doesn't read/write data from/to the NIC directly, it does it through the kernel's network stack. If sockets had no buffers, reading and writing would become too slow for any userspace application.

Kind regards