[strongSwan] Services unreachable after first connection

[Tobias Brunner]

Hi Tas,

> Do you think this strange behaviour can be cause by our strongswan
> configuration?

One thing that comes to mind in regards to TCP over IPsec are MTU/MSS
issues [1].  But those would only have an effect on larger transmits,
not on the initial TCP handshake.  That is, you should be able to create
a new TCP connection even after another stalled.  If that's not the
case, some firewall or routing issue could be the culprit (or a problem
with the IPsec tunnel on the other end).

By the way, you'll never see outbound plaintext traffic (e.g. a TCP SYN)
in tcpdump [2].

Regards,
Tobias

[1]
https://wiki.strongswan.org/projects/strongswan/wiki/ForwardingAndSplitTunneling#MTUMSS-issues
[2]
https://wiki.strongswan.org/projects/strongswan/wiki/FAQ#Capturing-outbound-plaintext-packets-with-tcpdumpwireshark