[Ilugc] more on firewall
We saw what a firewall can do at the kernel level with port numbers, ip addresses and other filter criteria found in the packet headers. It is easy to block by tcp or udp port numbers, block all ping packets(wrong), and you could block all packets with TOS byte fields of TCP flags corresponding to a SYN packet. But all that is only good for very basic firewalling. Not very useful in the real world. In the real world we want to block instant messaging, inspect https, look at p2p traffic and not just block but allocate bandwidth fairly and so on. These things require real engineering. The soft of things a networking engineer is supposed to do. QoS is nothing but traffic shaping or rate limiting of packets leaving our network. We can easily control that but what about packets coming to us? Nothing much we can do there. But with QoS we can get fairly good results in controlling network abuse. What if there is a buffer overflow attack or router worms? A firewall should be able to deal with such things. What if you want to do passive OS fingerprinting? A firewall can do that; block all SMTP traffic from Windows hosts. Now URL filtering is what people need. That a firewall cannot do. Only a userspace application can do that. And for that you have to redirect traffic by proxying. That is how you also get SIP, FTP and other traffic work across NAT boxes. A firewall has the important job of port forwarding. What is that? All incoming packets are blocked by default and being a local RFC1918 network they are anyway not going to reach inside. In order to enable that you can do the reverse of NAT. The packets to IP address and port can be rewritten to a local machine's IP and port. This is similar in functionality to ssh port forwarding but it is different in semantics. For port forwarding to work the routing should be symmetric and packets should be seen by the address rewriting engine(firewall) in both directions. We normally get this wrong and suffer in agony. There is a lot of other load balancing, traffic distribution and other advanced stuff that a firewall should do but even to get this far is quite a challenge. Firewalls should be able to separate network segments and manage what is called as DMZ where you can host your applications; which are accessible from outside world but you can't get into any other local machine from there. Unless of course you run the VPN software in it. ;) -Girish -- Gayatri Hitech http://gayatri-hitech.com ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] Panchtantra
Ha... Ha.. Nice! 2012/5/18 Shakthi Kannan > Hi, > > --- On Fri, May 18, 2012 at 7:47 AM, Jacob G Podipara > wrote: > | Moral: If you're not up-to-date with technology trends, > \-- > > Not necessarily true. There are lot of things that are exaggerated in > the market. > > SK > > P.S.: Please use [OT] in the subject line for such posts (off-topic). > > -- > Shakthi Kannan > http://www.shakthimaan.com > ___ > ILUGC Mailing List: > http://www.ae.iitm.ac.in/mailman/listinfo/ilugc > -- Regards, ARUN P A Tailor’s mistake is a Fashion But, An Engineer’s mistake is a Disaster. "Preserve the earth; Else we will perish" ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] Open Source Career Building Program – 1
Please reply to narasim...@ctsit.com or ama...@amachu.com privately or alternatively check Anna University site. Don't choke the group mailbox for queries thanks yessel On Fri, May 18, 2012 at 2:47 PM, yessel - எஸ்ஸல் wrote: > Dear ILUGCs, > Pl. spread the word: > > Attention: B.Com., B.Sc., (Maths, Physics), B.B.A., – 2012 passouts* - > *Become > an Open Source Professional* > > *Open Source Career Building Program – 1* > > *In two years you will get from* > > *Anna University: *Masters degree: M.Sc., (FOSS) > > *Amachu Infrasoft Services: *Mentorship, on Job Training, Study Environment > & Career** > > * > * > > *Eligibity Criteria* > > B.Com., B.Sc., (Maths, Physics), B.B.A., – 2012 passouts with 70% and > above > > > All you need is: > > Willingness to take up M.Sc., (FOSS) course at Anna University > > An interest to pursue a career in IT – Open Source > > > best > narasimhan > ___ > ILUGC Mailing List: > http://www.ae.iitm.ac.in/mailman/listinfo/ilugc > ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
[Ilugc] Open Source Career Building Program – 1
Dear ILUGCs, Pl. spread the word: Attention: B.Com., B.Sc., (Maths, Physics), B.B.A., – 2012 passouts* - *Become an Open Source Professional* *Open Source Career Building Program – 1* *In two years you will get from* *Anna University: *Masters degree: M.Sc., (FOSS) *Amachu Infrasoft Services: *Mentorship, on Job Training, Study Environment & Career** * * *Eligibity Criteria* B.Com., B.Sc., (Maths, Physics), B.B.A., – 2012 passouts with 70% and above All you need is: Willingness to take up M.Sc., (FOSS) course at Anna University An interest to pursue a career in IT – Open Source best narasimhan ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
Re: [Ilugc] a real mail server
On Friday 18 May 2012 07:57 AM, Mohan Sundaram wrote: > One member had mentioned fetchmail multidrop earlier. You can use that to > pick up mail from a single aggregated(called catch-all) mail bag on the > internet to distribute mails to users on the system running the MTA. To > deliver mail out, you can use the SMTP smarthost facility in the MTA to > forward all mails to another SMTP host assuming it allows you. I once ran a mailman this way :) Also have a look at 'getmail' as an alternative for 'fetchmail'. -- .o. I'm a Free man. I use Free Software. ..o ooo http://www.joesteeve.org/ signature.asc Description: OpenPGP digital signature ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
[Ilugc] [job] Fwd: [chennaipy 1332] Opening for Pythom Developers in World's largest mobile AD network
-- Forwarded message -- From: "swathi dharshna naidu" Date: May 18, 2012 1:08 PM Subject: [chennaipy 1332] Opening for Pythom Developers in World's largest mobile AD network To: Senior Software Developer - 10LPA 1. (Python) Minimum 5 years experience/things that match the experience Software Developer - 5LPA (2 people required) 1. (Python) 1-4 years of experience Jr. Software Developer - 3LPA (3 people required) 1. (Python) With deep product knowledge + experience is appreciated *Work Profile *Developers are responsible for building various key components of our ad serving system from the scratch Understand and evolve the logical architecture of the products Hack quick solutions to see how a particular component might work in a competitors product Coding as per the User stories Follow the SCRUM development model Build modular components that can be plugged into the the architecture that is to be built Build components that can maintain backward compatibility Use Github for version control Proven track record designing, implementing, deploying, and shipping high-volume and scalable software. *Knowledge *Strong CS fundamentals, data structures, algorithms Strong problem solving abilities Strong design and implementation abilities in any language preferably Python, but ability and willingness to learn new things. *Description *Lead the architecture for the product, write and review code, scope projects and milestones. Its ultimately up to you how you get things done, but we think in you will spend roughly 60-70% of your time coding, and the other 20-30% focused on building the engineering organization and scoping/designing product. In many ways, you will be part product manager and part engineer - we respect your opinion and believe you should feel passionate ownership for the things you make. We ask that you write scalable, maintainable, secure code and set the bar high when it comes to best practices of a professional software engineering organization including testing, source control, a dev/stage/prod release cycle and continuous integration and deployment processes. You have demonstrated ability to lead engineers and build a team. You are a prolific coder who can take a project and run with it, and have a track record of successfully building products that scale to large numbers of users. You have made significant architectural decisions. You are passionate about the engineering process, and you’ve used tools like Pivotal Tracker, Trac, Jira, FogBugz, or even post it notes to make sure everyone is on the same page. You’re down with open source. You're constantly experimenting with new technologies. You follow the Redis, Mongrel2 and the NoSQL drama with curiosity and interest. Formal training in computer science (bachelors, masters, school of hard knocks, whatever) *How to Apply: * Kindly sent us your resume/ CV with Github profile to our recruting advisor Ms. Swathi Dharshna swa...@explainwork.com. If any quries, please shoot us an email or call 08754029255. Thanks Folks. -- You received this message because you are subscribed to the Google Groups "Chennaipy" group. Wiki at http://nrcfosshelpline.in/chennaipy/ To post to this group, send email to chenna...@googlegroups.com To unsubscribe from this group, send email to chennaipy-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/chennaipy?hl=en ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
[Ilugc] "Thank To All !!"
Hi all.. I would like to thank all of you,who replied to all our queries.Really it helped us to learn a lot and based on your replies we proceeded further to attain our target. "THANK TO ALL" Thanks&Regards, S.Mohan. ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
[Ilugc] "THANK TO ALL"
Hi all.. I would like to thank all of you,who replied to all our queries.Really it helped us to learn a lot and based on your replies we proceeded further to attain our target. "THANK TO ALL" -- R.Marikkannan Linux System Admin SoftSolution4U ___ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
