# TCP won't work, but UDP & ICMP do...



## Jpop (Feb 22, 2000)

Hello, I'm posting this info for my friend that is have MAJOR problems. He's been through is system with a fine tooth comb, and NO ONE can help him thus far. You guys are my last resort. Here is the problem he is having, quoted directly from him...

"I have Win95 OSR2, with MS DUN 1.3. I can connect to my ISP. I can send & receive UDP & ICMP, but not TCP or any other protocol that negotiates a connection. I've completely uninstalled & reinstalled both old & new DUN from CD, more than once, to no avail. Winsock and its components all look fine. I've tried 3 different ISPs, two browsers, & a ton of other programs that use TCP...

Consistently, the only thing I can do are ping, traceroute, and send & receive ICQ messages (which defaults over to UDP, I think, if TCP won't work). Nothing else. No web, no email, no AIM, no ICQ chat or file transfer. I currently have no firewall installed. I'm using a vanilla dialup connection on a vanilla LT Winmodem. I know it's not a hardware/phone line issue....

IE5 tells me "Cannot connect to server or DNS error" (which is bogus, because ping & traceroute will correctly do DNS lookups). Netscape 4.7 tells me "TCP error: Not enough memory" (which is also bogus, unless it's referring to some obscure TCP/IP stack issue). I have a 200 MHz MMX w/ 160 MB of RAM. With everything running, I still have about 40 MB of unused physical memory. No other problems are occuring."

Please! Can someone help him? Please correspond through me, because of this problem.

Thanks!

Jason


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## LarryCore (Aug 26, 1999)

Is formatting the hard drive and reinstalling an option? That would probably be the easiest answer.

Has a full virus scan been run?

Has he checked to be sure that he does NOT have a HOSTS or LMHOSTS file in his Windows directory? It he does, he should delete them. Not HOSTS.SAM though - that's just a sample and is ok.

Has he made sure that IE and Netscape are NOT set to use a Proxy server?


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## Greg Freeman (Nov 20, 1999)

when you right click network neighborhood,and go to properties, what is listed under the configuration tab? If TCP/IP isn't there, add it. Click on your dial-up adapter under this tab, and click the properties button (or just dble click it). What are the binding set for? Is TCP/IP checked? Under the advanced tab, and let me know its values too. I may forget to check back cause I've been busy lately, if so feel free to email a reminder to me.
Hope this helps your friend.


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## Jpop (Feb 22, 2000)

Ok, my friend says this:

"I could reformat the C: drive, but that's a brute-force last resort I don't want to contemplate yet. I've run a full, up-to-date McAfee scan. I don't have HOSTS or LMHOSTS in my c:\windows folder. Nothing is using a proxy. My Network settings have the correct configuration for Dialup Adapter and TCP/IP --> Dialup Adapter. The Dialup Adapter's only binding is TCP/IP --> Dialup Adapter. 

The Advanced settings and the DNS settings have all been triple checked with all three ISPs. I've tried it with DNS enabled and disabled. I've tried specifying DNS servers in each dialup connection's Server Types TCP/IP Settings. Nada. I still get UDP and ICMP only. Nothing that uses the Net can get TCP in or out. This includes browsers, email, ICQ, AIM, PGP key servers, RealPlayer, Media Player, MusicMatch, ad nauseum.

I can do ping, traceroute, and ICQ messages (using UDP, presumably). I can see my IP address with winipcfg. I can't do Telnet, nor even FTP in a DOS box. Four networking engineers have walked me through various configurations, to no avail. I've totally uninstalled all services related to Dialup Networking & reinstalled clean copies from CD, more than once. Zilch. Ping & traceroute do DNS lookups correctly."

Thanks so much for all your help thus far! I hope we can get this problem resolved for him!


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## LarryCore (Aug 26, 1999)

Well, PING is a TCP/IP program. If it is working, then TCP/IP is working.

I am curious about something - have him download this mail checking program, and set it up to check his Email account and see if it works or errors out. If it works, I will no longer have ANY doubts about TCP/IP working correctly.
http://www.geocities.com/SiliconValley/Vista/2576/magic.html

BTW - this is a freeware mail alert program that I love. Easy to use and lets you check multiple accounts, set up different sound alerts, and some other stuff.


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## LarryCore (Aug 26, 1999)

I guess I should have said YOU download it, then take it to him - it is a small program so will easily fit on a floppy.


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## Jpop (Feb 22, 2000)

Larry,
He says:
"I downloaded that Magic utility (from someone else's PC, obviously). As expected, it didn't work. It said, "socket error!" whenever I attempted to connect to my mail server. I can add this one to the long list of Internet apps that won't connect to anything: browsers, email, chat, clock synchronizers, PGP key lookup, Real Player, Windows Media Player, McAfee, MS Office, etc.

As I said before, I can send and receive UDP and ICMP, but not TCP. Since the first two are generally single packet transmissions that don't require a connection, but TCP does, it would seem that the problem is in the TCP/IP stack or Winsock someplace. However, as I've said, I've completely uninstalled DUN & reinstalled (both old & new versions) from clean copies on CD.

Thus, I can do ping & traceroute (which are ICMP packets, if my clouded memory serves), and I can send/receive ICQ messages via the ICQ servers (which defaults over to UDP if TCP won't work). I have no proxies, no firewalls, and no strange apps competing for the modem. I've verified the version numbers, file sizes, and modification dates of all the relevant DLL's, .EXE's, and virtual devices I can think of. I get no GPFs or other errors.

Nothing strange is showing up in my Network bindings, TCP/IP settings, Device Manager, or the registry (at least, I haven't found any blatantly obvious registry keys that might be affecting anything). My MTU is set to 548 (yeah, I know that's a strange value, but it's the largest one that won't fragment, and it's been that way for about 2 years). My other settings (MSS, TTL, NDI, etc.) haven't changed in over a year.

I've tinkered with those settings, though, just to be sure. Nada.
Any ideas?
33"


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## LarryCore (Aug 26, 1999)

Doesn't look to promising...

How about Uninstalling IE5 then re installing Windows?


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