Firewall stopping HTTP POST requests

[veggen]

For some bizarre reason, ufw is *sometimes* preventing HTTP POST requests. GETs work normally, but POSTs hang forever. I know it's ufw because everything goes back to normal if I turn it off. Also, if I restart networking, it solves the problem temporarily. I don't have to do anything to ufw for it to start misbehaving. It can work normally for days before it starts blocking POSTs for no good reason.

Any clue what it might be?

Thanks.

[veggen]

Local Apache is unaffected. POSTs to it work normally.

[veggen]

*bump*

[Vishal Agarwal]

try enabling lo traffic in iptables

iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

[veggen]

Hey, thanks for taking the time to help me out!
Can you please give a little more insight into what the above commands are doing? I know what iptables is, but I don't really get what is being enabled here...

[veggen]

Didn't help
Anyone has any more ideas? Would be very greateful.

[cybpabeofm]

Could you give us more information? What data are you sending to servers exactly?
What port do you use and what packet type when you POST?

When it stops your POST run this command and please post up the output.

sudo ufw status

This will tell us what ufw is blocking and allowing

[veggen]

Well, I'm just doing a simple form submission. Take posting this response here on the forum for example. I had to disable ufw to do it.

While it was still on (and this post was still hanging indefinitely), the status returned this:

51413/tcp ALLOW Anywhere
51413/udp ALLOW Anywhere
51413/tcp ALLOW Anywhere (v6)
51413/udp ALLOW Anywhere (v6)

51413/tcp ALLOW OUT Anywhere
51413/udp ALLOW OUT Anywhere
51413/tcp ALLOW OUT Anywhere (v6)
51413/udp ALLOW OUT Anywhere (v6)

The rules you see are the predefined Transmission specific ones.
The screenshot of the ufw window is attached.

Does this help at all?

Thanks for putting time into this.

[veggen]

*bump*

[sourchier]

Try the following:

sudo su -

ufw allow http
ufw allow https

ufw disable && ufw enable

This should enable http (port 80), and https (port 443).

I hope this works for you.