gethostbyname_r returns NULL when hostname has dash


 
Thread Tools Search this Thread
Special Forums IP Networking gethostbyname_r returns NULL when hostname has dash
# 8  
Old 05-23-2008
Not sure but I am able to open through IE
# 9  
Old 05-26-2008
Actually Windows' resolver is known to simply drop illegal characters off the end of a host name if it helps to resolve it.
# 10  
Old 05-30-2008
This is wired output but as Era stated I could believe it:

From Unix box:

Code:
11> telnet nyustern-.collegemailer.com 80
telnet: nyustern-.collegemailer.com: Name or service not known
nyustern-.collegemailer.com: Unknown host

12> telnet nyustern.collegemailer.com 80
Trying 209.200.118.155...
Connected to nyustern.collegemailer.com.

From DOS command window:

C:\>telnet nyustern-.collegemailer.com 80


GET / HTTP/1.0
Host: nyustern-.collegemailer.com

HTTP/1.1 302 Object moved
Connection: close

But my issue is how can I resolve this at code level - what I need to do in such a case?

Last edited by uunniixx; 06-02-2008 at 03:04 AM..
# 11  
Old 06-02-2008
You can probably approximate what Microsoft is doing by simply dropping any illegal trailing characters.

By the by, the highlighted Server: header is a red herring; the issue is with how a Windows client would resolve the domain name.

If you can run tcpdump on the DNS traffic from the Windows box while it resolves and visits the site in IE (or simply opens a telnet session), you should see what host name the Windows box is actually resolving.
# 12  
Old 06-04-2008
I tried ways to dump tcp packets in windows and Unix but unfortunately unable to succeed cause I have a windows network login and ssh to unix development servers as developer.

Is there any other way I can do away with findings?
# 13  
Old 06-04-2008
You don't have any way to get access to a local Windows box? Lucky bastard. (-:

I believe there are VMware Player images with preinstalled Windows images you could play around with. Install Ethereal and watch it resolve. DNS is UDP port 53.
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

A dash to GOTO or a dash from GOTO, that is the question...

Well, guys I saw a question about GOTO for Python. So this gave me the inspiration to attempt a GOTO function for 'dash', (bash and ksh too). Machine: MBP OSX 10.14.3, default bash terminal, calling '#!/usr/local/bin/dash'... This is purely a fun project to see if it is possible in PURE... (3 Replies)
Discussion started by: wisecracker
3 Replies

2. UNIX for Advanced & Expert Users

Hostname -f hostname: Unknown host

deleted (0 Replies)
Discussion started by: hce
0 Replies

3. Red Hat

hostname command prints nothing a null value

Hi , On my box everything works fine. But whenever I run command It returns nothing as you see @(none) too. Its very strange issue I have never noticed on any other system yet. Any one have any idea about this. Thank you (2 Replies)
Discussion started by: pratapsingh
2 Replies

4. Emergency UNIX and Linux Support

HP UX - ILO Console hostname different than Machine Hostname...

Hi All, So we added a new HP-UX 11.31 machine. Copied OS via Ignite-UX (DVD)over from this machine called machine_a. It was supposed to be named machine_c. And it is when you log in...however when I'm in the ILO console before logging in, it says: It should say: What gives? And how do... (4 Replies)
Discussion started by: zixzix01
4 Replies

5. Shell Programming and Scripting

Insert string 'NULL' where there is a null value

I have an input file having 7 fields delimited by , eg : 1,ABC,hg,1,2,34,3 2,hj,YU,2,3,4, 3,JU,kl,4,5,7, 4,JK,KJ,3,56,4,5 The seventh field here in some lines is empty, whereas the other lines there is a value. How do I insert string NULL at this location (7th loc) for these lines where... (8 Replies)
Discussion started by: zilch
8 Replies

6. Shell Programming and Scripting

awk returns null?

hi i try to check if awk returns null and i dont know how it's works this is the command set EndByC = `ls -l $base | awk '/.c$/ {print $9}'` if ($EndByC=="") then #check if ther is XXX.c directory echo Sorry ther is no XXX.c folder "in" $base path echo the XXX.c folder is necessary... (6 Replies)
Discussion started by: frenkelor
6 Replies

7. UNIX for Dummies Questions & Answers

echo statement when find returns null

Hi, How do you echo something once when a find statement returns null results? This is when using mutiple locations and mutiple arguments. The below find command the inner loop of a nested for loop where the outter loop holds the $args and the inner loop holds the locations. find... (2 Replies)
Discussion started by: tchoruma
2 Replies

8. Shell Programming and Scripting

remove dash

hi I am using ksh #A="abc-def" #typeset -u B="$A" #echo $B ABC-DEF how to remove the dash? i.e. ABCDEF? thank you (1 Reply)
Discussion started by: melanie_pfefer
1 Replies

9. Programming

PEM_read_RSAPublicKey returns NULL

Hi all, I am trying to write a program in C which will generate private and public keys using openssl RSA and use these for encryption and decryption. I am able to generate the keys successfully and write these to files. I am able to read the private key successfully. I can encrypt and decrypt... (1 Reply)
Discussion started by: Treasa
1 Replies

10. UNIX for Dummies Questions & Answers

Solaris - unknown hostname - how can I change hostname?

Hello, I am new to Solaris. I am using stand alone Solaris 10.0 for test/study purpose and connecting to internet via an ADSL modem which has DHCP server. My Solaris is working on VMWare within winXP. My WinXP and Solaris connects to internet by the same ADSL modem via its DHCP at the same... (1 Reply)
Discussion started by: XNOR
1 Replies
Login or Register to Ask a Question