November 2009 - Test - lists.nanog.org

Network topology
by Colin Alston 15 Nov '13

15 Nov '13

Hi all I'm considering trying to come up with some means to automatically detect a networks topology and draw pretty pictures. This is somewhat boring though if a network isn't well arranged with VLANs and q-tag trunk routers and so on (It will just look like a big cloud of junk connected off an assumed switch). Is there any kind of cunning trick to detect standard layer2 switches along a path without stuff like STP?

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Inventory and workflow management systems
by vijay gill 26 May '13

26 May '13

What software solution do people use for inventory management for things like riser/conduit drawdown, fiber inventory, physical topology store, CLR/DLR, x-connect, contracts, port inventory, etc. Any experiences in integrating workflow into those packages for work orders, modeling, drawdown levels, etc. /vijay

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ISP port blocking practice
by Zhiyun Qian 13 Sep '10

13 Sep '10

Hi all, What is the common practice for enforcing port blocking policy (or what is the common practice for you and your ISP)? More specifically, when ISPs try to block certain outgoing port (port 25 for instance), they could do two rules: 1). For any outgoing traffic, if the destination port is 25, then drop the packets. 2). For any incoming traffic, if the source port is 25, then drop the packets. Note that either of the rule would be able to block outgoing port 25 traffic since each rule essentially represent one direction in a TCP flow. Of course, they could apply both rules. However, based on our measurement study, it looks like most of the ISPs are only using rule 1). Is there any particular reason why rule 1) instead of rule 2)? Or maybe both? Also, is it common that the rules are based on tcp flags (e.g. SYN, SYN-ACK)? One would think block SYN packet is good enough. Regards. -Zhiyun

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Upstream BGP community support
by Andy B. 04 Jun '10

04 Jun '10

Hi, Quick question: Would you buy transit from someone who does not support BGP communities? Here is the story: My company is pushing several GBit/s through various upstream providers. We have reached the point where we rely on BGP communitiy support, especially communities that can be sent to the upstream to change the way he announces our prefixes to his peers/transits. While most decent upstream providers support this kind of traffic engineering, one of them refuses to send and accept BGP communities. I tried to contact my upstream several times through different channels to get some background as to why they would not be able to provide us this service, but all we get is tickets that get closed without an answer. Management itself does not seem to bother either. Is this normal or is it too much to ask for BGP communities from an upstream who has points of presence in the US, Europe and Asia? Andy

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Wireless bridge
by Peter Boone 05 Apr '10

05 Apr '10

Hi NANOG, I'm looking for some equipment recommendations for a wireless bridge between two locations approximately 500-800 meters apart. The current setup for this company has been extremely unstable and slow. I don't have a lot of experience in this area so I was hoping someone could give me a few pointers. Currently, both locations are using Linksys WRT54GL's flashed with DD-WRT firmware (Yes, 802.11g. All extra bells and whistles are disabled in the firmware. They were set up for WDS so other wireless clients could connect to the same access point, with varying degrees of success. Not very important). They are connected to SmartAnt 2300-2500 MHz 14 dBi directional antenna mounted on the roof (extended pretty high for perfect line of sight). I'm not sure when they got these antenna exactly but I'm told it was when WiFi was very new. The network is very small so both locations share the same subnet (192.168.1.0/24). They have gone through numerous Linksys access points over the years. The wireless settings are tweaked as best as possible, and we have found the connection to be most stable when the TX is limited to 6-9 Mbps. We have explored other options as well. An internet connection at each location + VPN is out due to very slow upstream speeds (the buildings are in an industrial area, ADSL is the only option.) The max they offer on regular business accounts is 800 kbps up. T1 lines are even slower and even more expensive. They won't offer us any other solutions such as fibre. We have considered running fibre/coax but there is too much construction activity and other property in the way. I'm looking into RouterBOARD right now, considering a RB433AH and R52H wireless card, but I'm not sure this will actually solve the problem. It's difficult to determine if the issue is with the antennas or access points (for example, after a good thunderstorm, the wireless link will be down for at least 12 hours, but will fix itself eventually. Resetting either access point will keep the link down for at least 30 minutes. Using an airgun on the access points tends to make them more reliable, even if they are clean and dust free. From the admin interface, each access point will report seeing a very good and strong signal from the other, yet they refuse to communicate until they feel like it a few hours later.) Any suggestions welcome. I'm sure you can tell cost is a bit of a factor here but it will be easy for me to justify a higher price if I'm confident it will be effective. While I'm at it, I've been reading along on the list for over a year now; thanks everyone for sharing your real world experiences :) Peter

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Voice Operators' Group: voiceops.org
by Hiers, David 12 Feb '10

12 Feb '10

Hi Everyone, I'm pleased to announce that the Voice Operators' Group has found an excellent home. Our web site, www.voiceops.org has a good home (thanks Scott!), while Jared, Daniel, and all the great folks over at nether.net are hosting our list server. If VoiceOps can do for voice anything close to what NANOG has done for IP, we'll all owe much to the people that are making this happen. email: voiceops-subscribe(a)voiceops.org web: https://puck.nether.net/mailman/listinfo/voiceops Thanks, David Hiers CCIE (R/S, V), CISSP ADP Dealer Services 2525 SW 1st Ave. Suite 300W Portland, OR 97201 o: 503-205-4467 f: 503-402-3277 This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system.

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ARIN/RIPE NCC Joint Statement on ASN Assignment Discrepancies
by John Curran 09 Dec '09

09 Dec '09

ARIN and the RIPE NCC have worked together to research the issues with the Autonomous System Number (ASN) range AS1707-AS1726. Below is our analysis of what happened and a plan to resolve these issues. It appears that prior to 1993, Renater was issued AS1707 with an AS name of "ASNBLOCKA". This is the name format used to assign a block of ASNs, but the DDN NIC (the Defense Data Network Network Information Center, which was responsible for ASN assignments until 1993) recorded only a single assignment of AS1707, rather than the entire block of 20 ASNs (AS1707-AS1726), as would have been expected. AS1712 was never registered in the DDN NIC database. Since the proper registration was never recorded, this mistake carried over from the InterNIC database into ARIN's database at ARIN’s inception in 1997. The ASN range was not transferred to the RIPE NCC along with AS1707 because AS1708-AS1726 appeared to be unassigned, and thus remained with ARIN. Because this is simply an error in registry data and Renater is the actual registrant of this entire range of ASNs (AS1707-AS1726), ARIN will work with its customers who received ASNs from this range in July and August of 2009 to provide them with replacement ASNs. While we understand that this may cause some difficulty for these customers, we feel that this is the best path forward given the circumstances. RIPE NCC and ARIN will update their respective databases and work with the IANA to ensure that the ASN registry data is properly updated for this range. To prevent future issues, ARIN and RIPE NCC will implement two new processes for issuing new ASNs: checking all other RIR databases to ensure that the ASN is not previously registered, and checking BGP routing tables to ensure the ASN is not already found in an announced AS-path. ASNs that fail either of these conditions will not be issued until the discrepancy has been addressed. Regards, John Curran, President and CEO, ARIN Axek Pawlik, Managing Director, RIPE NCC

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Route Target rewrite
by shake righa 04 Dec '09

04 Dec '09

Anyone with material on how to perform route target re-write as well as filtering during vpnv4 BGP sessions. Have been ttying but the rewrite is not occuring. Regards, Shake Righa

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AT&T SMTP Admin contact?
by Brad Laue 03 Dec '09

03 Dec '09

Hi all, Would I be able to get an AT&T mail administrator to contact me off-list? We've recently moved our mailservers to a new IP address range, and the standard CGI forms haven't produced any progress for us in over a week now. Unfortunately this affects dozens of hosted clients... The CGI form at http://wn.att.net/cgi-bin/block_admin.cgi has also got a dead link at the bottom, which shakes my confidence in its level of maintenance a little. Thanks in advance, -- Regards, Brad Laue Systems Administrator, Inftek Hosting 1-888-44-SYNCD http://www.getsyncd.com (888) 44-SYNCD (888-447-9623) x702

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What DNS Is Not
by Alex Balashov 03 Dec '09

03 Dec '09

Thought-provoking article by Paul Vixie: http://queue.acm.org/detail.cfm?id=1647302 -- Alex Balashov - Principal Evariste Systems Web : http://www.evaristesys.com/ Tel : (+1) (678) 954-0670 Direct : (+1) (678) 954-0671

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