When you need to troubleshoot SMTP issues, it is a known fact that a simple telnet to port 25 of the SMTP server in question would get you far. It will get you to see the problems. When connecting to Office365 (outlook.com) to relay mail, and you want to check how things work, you can…
The idea in general is to have multiple wireless networks at home – one for the house residents, the other for visitors. The home network should have full access to everything, while the guest network should be able to reach the Internet, but nothing else. I have Asus RT-AC87U, which is a fine router, but…
I use this blog as an external memory. I found myself lately looking for the obvious patches for Oracle GI and RDBMS products, and although I eventually reach the right location, the time consumed looking for them is a wasted time. So – to make sure I can remember them correctly, here are the two…
(This article is the essence of a post from this Redhat Archive and it goes as follows: Problem: You need to detect what deletes files on your Linux Solution: Using auditd, with the right flags, you could get a lot of information. In Practice: If the mount point/directory is /oracle, then: (as root:) auditctl –w /oracle -k whodeletedit -p…
Assume a server has two network interfaces as follows: eth0 : 192.168.0.1/24 eth1 : 192.168.10.1/24 Let’s assume these interfaces reside on the different VLANs. Lets assume they were connected incorrectly, in such a way that eth0 is connected to VLAN 10, which servers 192.168.10.0/24 and eth1 is connected to VLAN 2, which serves 192.168.0.0/24. You…
As far as routing goes, it is a very bad idea to place multiple network interfaces with IPs of a single network (subnet). The routing table, which decides which interface to route the data through, reads the table line by line, thus – all traffic goes through a single interface of the batch (-> of…
