{"id":63,"date":"2005-09-09T00:01:10","date_gmt":"2005-09-08T15:01:10","guid":{"rendered":"https:\/\/regex.info\/blog\/2005-09-09\/63"},"modified":"2005-09-09T00:06:01","modified_gmt":"2005-09-08T15:06:01","slug":"a-wasted-day-futzing-with-networking","status":"publish","type":"post","link":"https:\/\/regex.info\/blog\/2005-09-09\/63","title":{"rendered":"A Wasted Day Futzing With Networking"},"content":{"rendered":"

I had a miserable day fighting with networking issues today. You don't\nwant to hear about it, unless I ended<\/span> up solving the same problem you have\n(which is why I'm writing this -- for the search engines to pick up).\n<\/p>\n\n

A few days ago, some web sites suddenly seemed mostly unaccessible\n(accessible, say, 5% of the time), while others were just fine. Since most\nYahoo! sites were among the missing, this was a big<\/span> problem.\n\n<\/p>

The other day I was able to pinpoint that the problem occurred when\nI used<\/span> my router (Corega\nBAR-SD<\/a>) inline between my ISP<\/a>\nand my computers. So, today I tried<\/span> to get to the bottom of it.\n\n<\/p>

Upgrading the router's firmware didn't solve the problem.\n<\/p>

“The problem”, in this case, is that I could<\/span> connect to\nsome sites, but nothing would be returned before the connection would time\nout. So, I installed<\/span> Ethereal (now called “<\/span>Wireshark<\/a>”<\/span>), a network<\/span>\nprotocol analyzer, to watch what was happening. I'm not a<\/span> network expert by\nany means, but I could<\/span> see that there many duplicate ACKs, which is\nprobably not good.\n\n<\/p>

My brother<\/a> recommend that I also<\/span>\nsniff the traffic on the other side of the router, to see if the traffic\nwas leaving the router properly. So, I went through<\/span> the hassle to put one\ncomputer on the outside of the router, and another on the inside, and then\ntried to watch what happened as the from-the-inside request timed out.\n\n<\/p>

Unfortunately, I used a<\/span> switch rather than a hub<\/span> to hook up both the\nrouter and the outside-the-router computer to my ISP, which means that the\noutside-the-router computer didn't see any traffic from the router itself.\nDoh. I don't<\/span> have a non<\/span>-switching hub. Sigh.\n\n<\/p>

In the process of this, though, I'd run Ethereal<\/span> on my wife's XP box\nand noticed that some apparent nasty-ware was contacting\n“offerapp.com” (67.29.139.222) serendipitously. So, this\nstarted the tangent of running the Anti-Spy component of Yahoo! Toolbar<\/a> and Microsoft\u00ae\nWindows AntiSpyware<\/a>, but a subsequent<\/span> test still showed the traffic.\nSigh. Must look into this later.\n\n<\/p>

Back to my router problem, I decided<\/span> that the router is probably\njust bad, so I rode<\/span> my bike down to the Teramachi Joshin Denki<\/a> to pick up another. While\nlooking for one, I noticed<\/span> that they didn't seem to sell a non<\/span>-switching\nhub. Still, I should<\/span> probably have one on hand just for the type of\nnetwork-sniffing task I ran<\/span> into today.\n\n<\/p>

Anyway, I ended<\/span> up dropping $50 on a Corega\nBARF-X2<\/a> router. (It's actually called “BAR-FX-2”, but it's\nmore fun to write as “BARF-X2”.) Despite the previous Corega\nrouter apparently dying not much more than a year<\/span> after having bought it, I stuck<\/span> with the Corega over Buffalo (the other choice) because the BARF-X2\nwas likely to have a “PC Database” feature (see sidebar\nbelow).<\/p>\n\n

Router “PC\nDatabase” Feature<\/big><\/center>\n\n

What Corega calls its “PC Database” feature may well be a\ncommon<\/span> feature among today's routers, but I'd not heard of it at all until\nnoticing it this week while futzing with my old Corega\nBAR-SD<\/a>.\n\n<\/p>

It's a feature which allows you to reserve a specific<\/span> IP in the\nDHCP pool for a specific<\/span> computer (that is, for a specific<\/span> MAC address).\nThis allows me to, for example, set it up so that my laptop always gets\n192.168.1.4, yet still leave the laptop's network settings at the simple\n“use DHCP” settings. It indeed<\/span> uses DHCP, but because I've\nassociated its MAC address with .4 in the router, it always gets .4.\n<\/p>

This is very cool, especially when NAT and port forwarding are\nconcerned: you can safely forward traffic to an IP and know that it\nwill always reach the specific computer. My dad's router didn't have\nthis feature, and sometimes after a power<\/span> interruption, if he's unlucky,\nhis computer won't get the IP he had before -- the one that has some ports\nhis computer needs forwarded to it -- and he's boned. This “PC\nDatabase” feature would solve that.\n\n<\/p>

One small issue is that while the BAR-SD showed computer names and\nWAP identifiers in its list of connected systems, the BARF-X2 does not.\n)-:<\/b> <\/p><\/div>\n\n

So, things worked just fine with the new router, but I was<\/span> still\nwondering if I should<\/span> put my Vonage<\/a> VoIP\nmodem (Motorola\nVG1005v<\/a>) between the ISP and my router, or just as a client<\/span> of the\nrouter. It's simpler<\/span> for me to just put it as a client<\/span> of my router, but\nthere are some benefits to putting it inline before the router. One is that<\/span>\nit will give voice traffic priority over data traffic. However, while that\nmight make an important difference on a small<\/span> DSL\/Cable pipe, it's not\nrelevant on my 50 Mbit uplink (it's advertised as 100 Mbit, but a speed<\/span>\ntest got only about half that).<\/p>\n\n

Another benefit of putting the VoIP modem first is that I used<\/span> its MAC\naddress when signing up for a fixed<\/span> public IP from my ISP. Currently, I get up<\/span> to 5 private addresses (the whole building is behind NAT), but once they\nget the paperwork I sent<\/span> in the other day, they'll give me a public<\/span> IP ....\nbut only when the device I registered<\/span> connects. In a fit<\/span> of stupidness the\nother day, I'd given<\/span> the VoIP modem's MAC address. If I put<\/span> the router\nfirst, I'll continue to get the private addresses.\n\n<\/p>

While rummaging around the VoIP modem's configuration screens, I turned<\/span> off the “DHCP\/NAT on LAN Port” feature. I had an<\/span> idea\nwhat it would do, but wasn't quite sure, so gave it a try.<\/span> In one sense<\/span>,\nthe result was as I expected<\/span> -- putting things downstream of it connected\nto my ISP as if it wasn't there. What I didn't<\/span> (and still don't) know is\nhow the modem itself connects in this situation. I suppose<\/span> it's a DHCP<\/span>\nclient itself, consuming an IP, but I don't<\/span> really know.\n\n<\/p>

Anyway, I then ran<\/span> into the problem of how to turn the DHCP\/NAT back\non. To do that<\/span>, I needed<\/span> to access its menus (at the fixed address of\n192.168.102.1, via its LAN port), but since my ISP was giving me address\nlike 172.16.126.241 (and I was<\/span> getting those even when connected downstream\nvia the LAN port), I felt pretty<\/span> stuck.\n\n<\/p>

Fast-forward several hours of futzing around and I finally<\/span> figured\nit out: Hooked things up as ISP -> Router -> VoIP ->\nComputer<\/b> and set my router to 192.168.102.5. I was then<\/span> able to see\n192.168.102.1 (the Motorola VoIP modem) from the computer, and turn\nDHCP\/NAT back on. Ugh. Then set the router back to 192.168.1.1 where I like<\/span>\nit, and reconfigure things so that the VoIP Modem is a simple<\/span> client of my\nrouter, as are all my computers (and nothing is downstream from the VoIP\nmodem)\n\n<\/p>

By the way, why did I care about turning DHCP\/NAT back on? In case we<\/span> bring it with us somewhere, we want to be able to put it inline with our\nsingle-IP connection and still connect with a computer<\/span> plugged into the\nback of the modem. <\/p>\n","protected":false},"excerpt":{"rendered":"

I had a miserable day fighting with networking issues today. You don't want to hear about it, unless I ended up solving the same problem you have (which is why I'm writing this -- for the search engines to pick up). <\/p>

A few days ago, some web sites suddenly seemed mostly unaccessible (accessible, say, 5% of the time), while others were just fine. Since most Yahoo! sites were among the missing, this was a big problem. <\/p>

The other day I was able to pinpoint that the problem occurred when I used my router (Corega BAR-SD) inline between my ISP [...]","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts\/63"}],"collection":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/comments?post=63"}],"version-history":[{"count":0,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts\/63\/revisions"}],"wp:attachment":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/media?parent=63"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/categories?post=63"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/tags?post=63"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}