4
votes
4answers
272 views

Why on linux machines, any packets do not pass except icmp, but correctly pass on windows

There is a cluster on proxmox. In a cluster have vm - configured router (pfsense). In the our net have Windows and Linux machines. There is the problem: Windows-machines have access to the internet, ...
0
votes
1answer
70 views

Server sending packets every 5 minutes to 3 IPs

Been noticing in our firewall logs that three connections are being constantly established every 5 minutes from our web server and trying to send a packet to destination port 43 (whois port) cycling ...
0
votes
3answers
398 views

Monitor traffic between two network switches using a transparent firewall

For debugging reasons i need to see what network traffic especially TCP is transmitted or not. I thought about using an Endian firewall for this, but it doesn't support 2 network interfaces with the ...
1
vote
7answers
3k views

Firewall blocks traffic - how to find out what ports / ip addresses are used by software?

Well I get a "host was not accessible" error when trying to use a software. I don't know which port they use nor which address they are trying to reach. Is there a more or less easy way to figure that ...
4
votes
1answer
208 views

Can tcpdump tell accessed port numbers?

I have a server with two NICs, and I would like to only have those ports open on eth1 that are being used. Question How do I get tcpdump to tell me the port numbers that is being accessed on eth1?
3
votes
1answer
644 views

tcpdump output with iptables REJECT policy enabled

Quick question. I have a firewall with these simple rules: iptables -A INPUT -p tcp -s 127.0.0.1/32 --dport 6000 -j ACCEPT iptables -A INPUT -p tcp -s 192.168.16.20/32 --dport 6000 -j ACCEPT ...
0
votes
2answers
552 views

Howto monitor traffic between IIS and MSSQL

I am trying to check how much traffic is flowing between MSSQL Server and IIS Server in different locations. There is 1 ipcop in every location and I download the tcpdump file from one firewall and ...
0
votes
1answer
538 views

openvpn dual install (client and server) routing problem

I have the following install: PROD net (10.88.88.0/24) OFFICE net (192.168.2.0/24) on PROD I have openvpn server (vpnprod), so OFFICE can connect. on OFFICE I have openvpn machine (vpnoffice) ...