On my Debian server running a Django website, I have an error when I need to send an email.
The error received is
Exception Type: gaierror Exception Value:
[Errno -2] Name or service not known
Exception Location: /usr/lib/python2.6/socket.py in create_connection, line 547
You can see the full error log here.
After testing, it seems it is my firewall that blocks the request. You can see my iptable file (/etc/init.d/firewall). I think the problem comes from the two commented lines that were supposed to accepts all established connections.
When I uncomment them, I have an error
iptables: No chain/target/match by that name.